No advantage holds up against hard work no matter how insurmountable the disadvantage against privileged foes. Hard-working paraplegics are able to out-speed sports cars without so much as a wheelchair.
Miki trains alongside everyone else.
Alternately: her relatively relaxed training schedule takes its toll when her more diligent compatriots overtake her.
...However, it's later revealed that her gifts just make her naturally stronger and let her breeze through the exercises.
...only for her to overtake them again in no time when she starts training seriously.
Parodied: The show has a Training Montage where her friends go through Training from Hell to grow strong enough to form a Hero Secret Service, intercut with scenes of Sangria herself exercising her vast powers in preparation for their fight. Everyone wonders what super secret training Miki is going through to unlock her true power, and speculate she's pushing herself in her training, so they in turn train harder. What's Miki doing through all this time? Watching reruns of Friends and eating potato chips and cream soda.
Miki doesn't do hard work and randomly switches from ultra-powerful to How Do I Shot Web?.
Exploited: Since she doesn't need to train to increase her powers, Miki uses the time she would spend training to get a degree instead. Once Queen Sangria is defeated, she easily transitions to civilian life as a lawyer.
Defied: Miki realizes her immense potential means she's likely to slack off, so she finds/hires a mentor or trainer to help her training be an actual challenge.
Discussed: "I worry about Miki not training. Sure, she always wins and is stronger than everyone else, but what kind of message is that to the children? Just think how resentful the rest of her teammates are! Queen Sangria will Divide and Conquer us."
Conversed: "Do the superheroes in this show even do anything to keep up their strength?"
Since she doesn't have to work for her immense powers and knows that she's The Chosen One, Miki becomes snobby and narcissistic, looking down upon those who require training. This creates a rift between Miki and the very people she's supposed to save one day, leading to others rejecting andbelittling her. When the time comes for her to finally face Queen Sangria, she's overconfident and underprepared, leading to her getting trounced.
Since Miki was doing so well without training, people significantly less skilled try following her steps. Disaster ensues.
Miki feels alienated from her peers because of her immense power, so she purposely avoids training to stay near their level. Effectively, she's a super-super human who wants to be just "super". Eventually, her mentor and friends will remind her that With Great Power she must also train a great deal to save the world.
Just because Miki doesn't get much out of hard training doesn't mean that she can't work hard in some other helpful capacity. It just means that while her friends are training, she's helping out with Habitat for Humanity or running soup kitchens or cleaning up highways—non-training work that still needs to be done.
Played For Laughs: Miki exaggerates the fact by flaunting enemies with pictures/video/Trash Talk of her goofing off while they work to get their power... and once they're good and angry, lures them into a Defensive Feint Trap. She goes on to point out that just because she gets more power with less effort, she's neither dumb nor lazy.