>>39463167That's like asking why the entirety of the 2008 Detroit Red Wings aren't out stopping crime.
They're essentially just good at doing sports.
Though using the Gym Leaders more in general makes sense, this was one of the many failures of Gen 5. They never should've shown up there. It makes no fucking sense.
The only reason the player characters are doing so is because it's a fucking game and they're giving you a reason to play it. It's not because Pokémon users are inherently good at this. They're just the chosen one.