It's awesome, powerful, unstoppable... but not as useful as it might seem (if it's useful at all).
Yes, it seems that the designers put so much time into maxing out the "ultimate" factor of the ultimate attack that they forgot to actually make it usable. Maybe it requires too many resources to use, causing its allure of "awesome" to be lost as fast as your party's money. Maybe it requires some sort of bizarre set-up to enact, making your normal attacks and spells much easier to apply inside of battle. Maybe it has a considerable chance of failing or backfiring that makes it unreliable from the start. Maybe by the time you get it, there's nothing worth using it on. Or maybe in mathematical terms it doesn't deliver as much bang for the buck as "inferior" alternatives.
Whatever the reason, it will get used once, as a test drive, and then never again. Yeah, it's amazing, but you've got a game to win here. It's Awesome, But Impractical.
Keep in mind, Awesome, But Impractical is not Cool, but Inefficient, which is where something appears to be awesome, but has no real benefit to using. Awesome, But Impractical is genuinely useful in the right circumstances — it just requires such a cost and/or is so ridiculously conditional that you're probably not going to use it very often. Sometimes, Awesome, But Impractical moves carry a situational advantage, or are so Difficult, but Awesome that even highly skilled players have trouble using them — but there is an advantage over normal moves if you can afford to pay the penalties and/or work around the drawbacks. Sure, maybe that mini-nuke will irradiate and possibly kill your party, but if you're in a big enough pinch, possibility of death beats guaranteed death, so you may as well try it.
The very act of using a million tons of firepower on a few weaklings (a.k.a. overkill) is also Awesome, But Impractical.
Mind you, if you care about doing cool stuff over winning, they can be quite fun. A competitive player will never look at them twice; this can be one of the good things about being a Noob.
Related to the Bragging Rights Reward and Inventional Wisdom on occasion. See also Useless Useful Spell, Blessed with Suck. Contrast Too Awesome to Use, Boring, but Practical, Game-Breaker, Simple, yet Awesome. Compare and contrast Difficult, but Awesome; there, the focus usually is on Impractical turning out to be Awesome. Crosses with Death or Glory Attack when a miss will result in nasty consequences, and Powerful, but Inaccurate when lack of accuracy is the reason for the impracticality. Scary Impractical Armor is a Sub-Trope, as well as Impractically Fancy Outfit. In Real Life, this trope is often the reason behind I Want My Jet Pack.
Please add only examples whose impracticality is shown within the work. If it works fine in-universe but later thought renders it clearly impractical, that's Fridge Logic.
- Anime & Manga
- Comic Books
- Fan Works
- Live-Action TV
- New Media
- Tabletop Games
- Video Games
- Western Animation
- Real Life
- In Motu Patlu, a lot of Dr. Jhatka's inventions sound cool or even awesome on paper, but in practice they get people in trouble more often than not.
- The Creature-Hunter Organization D.H.O.R.K.S. from Helluva Boss seems to fight exclusively with weapons from Edo period Japan. When the group ends up getting slaughtered in a Curb-Stomp Battle against I.M.P (who, besides being physically stronger than any D.H.O.R.K.S. member due to being demons, have guns and far more practical melee weapons), Agent One questions why they only use these weapons instead of something actually more useful. Agent Two's answer? Because the Edo period was badass.
- Marckus' Stake-jacket from Hunter: The Parenting. It can be used to stake any vampire that attacks him from the front, but it's useless at any other angle, requires him to put himself in danger, and runs the risk of him staking himself with one wrong move.
- Murder Drones: The protagonist Uzi creates a railgun design to fight the titular Murder Drones. When she is actually able to use it, the blast is powerful enough to blow one's head off in a single shot. However, this one shot is likely all one would get as it requires about 30 minutes to recharge and the Murder Drones also possess a potent regeneration ability and can simply repair the damage done to them, meaning that the shot will only be a temporary setback unless both the head and torso are destroyed.
- False Swipe Gaming: Reshiram boasts the unresisted STAB combo of Dragon/Fire,note and can 2-hit KO just about anything in Gen 5. However, its inability to switch in safely, vulnerability to entry hazards, and low speed rendered impractical to use. And when Kyurem-White was released and did everything Reshiram did but better, Reshiram was rendered unviable.
- Tulok the Barbrarian discusses it with some of his builds, which are more focused on character consistency than Min-Maxing. Builds that dump Constitution (i.e. All Might and sans) are never really good ideas because of how vulnerable it makes you, multiclassing Monk/Barbarian isn't optimal by any means, focusing on a specific element will hobble you if the monster happens to be immune to that element, and characters who focus on support or trickery often have very little methods of actually dealing damage.
- Discussed beautifully in Vision of Escaflowne Abridged.
Merle: Fossilized dragon hearts, stupid. They use them to power Guymelefs.
Van: That's why I had to kill a dragon before I could claim Escaflowne and become king. In a war, the side with the most energists usually wins.
Hitomi: ...Huh. And Zaibach mines them in mass quantities?
Hitomi: And your people get them by killing live dragons in single combat?
Van: Yup! ...When you put it that way, it sounds pretty stupid, huh?
Hitomi: A little bit, yeah.
- Discussed in the video 5 Most Insanely Massive Projects Never Completed by Dark5:
- Project Atlantropa: A plan to dam the Strait of Gibraltar in order to provide power for the entirety of Europe and much of North Africa and the Middle East. In the process, it would've caused the sea levels in the Mediterranean to drop by 200 meters, creating a land bridge between Spain and North Africa. While the power output of the resulting structure would have been more than enough to meet the area's energy needs, the amount of money and manpower needed to construct it would have been unfeasibly high, and the resulting environmental damage to the Mediterranean Sea would have been downright catastrophic.
- Project Plowshare: An attempt to use nuclear explosives for peaceful, non-military purposes such as oil fracking and natural gas extraction. Not only was it soon done in by public opposition and international treaties banning the underground detonation of nuclear weapons, but the oil and gas extracted was of very poor quality in addition to being contaminated by radiation from the explosives.
- Project Mohole: An attempt to drill into the Mohorovičić discontinuity — the boundary layer the between Earth's crust and mantle — via multiple super-deep boreholes on the ocean floor and bring up core samples. Not only was the project criticized as a waste of funds that could have been better used for other scientific endeavors, but very little useful information on the planet's internal composition was obtained anyway.
- Welthauptstadt Germania: Nazi Germany's plan to rebuild Berlin in their image and serve as the capital of their proposed Greater German Reich. Their proposal would have seen the construction of such megastructures as a Triumphal Arch six times the size of the Arc de Triomphe and a domed People's Hall the size of several city blocks. The end results would not only have been too heavy for the city's soft soil to handle, but would have created an utterly inhospitable living environment for the city's ordinary citizens. On top of all that, thousands of Jews, Romani, homosexuals, and political prisoners were worked to death in order to facilitate its construction. Only a handful of the proposed structures were built, and most were demolished after the collapse of the Nazi regime.
- Project Pluto: A proposal for a cruise missile utilizing a nuclear-powered ramjet engine. While its range would have been far greater than any other cruise missile at the time, it would irradiate everything in its path, making it impossible to fly over friendly territory or even launch from American soil, and was quickly rendered obsolete by the development of intercontinental ballistic missiles.
- SMPEarth: Planes — they can achieve high-speed flight, but require fuel and cost a lot. Wilbur Soot tried to capitalize on this by building a paywall bridge across the Atlantic ocean, but that became awesome but impractical in itself, because Wilbur was killed seven times while building that bridge.