I just thought it would be a nice little feature to be able to battle Gymleaders and their Pokémon.
If you beat them, there could be the Sprite of the badge added to your Trainer's stats. This way, you can battle them and your Pokémon get some experience. And if you defeat them you earn some money. It could be made so that higher levels are required to battle other Gymleaders so it would be a real challenge to get them all. ( For example: Brock with Rock-type Pokémon on Lvl. 5, Misty with Water-type Pokémon Lvl. 10,......)
If you beat them, there could be the Sprite of the badge added to your Trainer's stats. This way, you can battle them and your Pokémon get some experience. And if you defeat them you earn some money. It could be made so that higher levels are required to battle other Gymleaders so it would be a real challenge to get them all. ( For example: Brock with Rock-type Pokémon on Lvl. 5, Misty with Water-type Pokémon Lvl. 10,......)