[[WMG: Why the heck does Pinkie do the whole {{Homage}} thing?]]
Sure, there might be a whole conservation of joke thing going on, but despite the ability to, no doubt, take advantage of CutscenePowerToTheMax, her [[VideoGame/FinalFantasyX2 DressSpheres]] seem more a limitation than anything else, and worse, they exacerbate her WeaksauceWeakness. You can't make your [[YourMindMakesItReal check to disbelieve]] until you make your [[FailedASpotCheck Spot Check]], after all. Which is funnier: using [[VideoGame/SplinterCell night-vision goggles]] to spot an invisible opponent, or to WesternAnimation/MrMagoo your way through a fight? Worse, while it may be impossible for the [[GogglesDoNothing goggles to do anything]], the other is merely improbable.
* Of course, there's the whole meta answer: it's precisely to tone her down and keep her manageable for the author, although it also gives her room to grow as she moves away from over arching gimmicks.
** The downside to the 'growth' answer, of course, is that that's pretty much where she started out in canon...
[[WMG: Why can't Twilight make cupcakes out of rocks when she can make a top hat out of a rock?]]
Top Hats and Rocks are both made out of inorganic material. A cupcake is not.
* Actually most Top Hats in the Real World are made out of felt and stiff cardboard or leather bound book-like substances. It is in fact organic. Perhaps the top hat she crafted is just reorganized rock material which makes more sense.