Starting in Pokémon Crystal, you could choose to play as a girl! Sometimes there are even little differences depending on what you choose, like who your rival is. In Smash, though, it’s a purely visual change, so play whoever you like best. This specific trainer is Leaf, the female trainer from Pokémon FireRed & Pokémon LeafGreen. Like Red, Leaf is from Kanto, so it makes sense she’d use the same Pokémon.