>>39166392It's a mechanical/presentational abstraction.
Limiting them to water battles is a fucking terrible idea and serves nothing but "realism" while denying them use in the vast majority of gameplay contexts. The only other option would be to create a specific arena type for every existing arena type that includes "water sections", and that can pick and choose for all four slots in a double battle AND can naturally transition between water and land if you switch out. Which obviously doesn't make sense, unless you know a way you could summon a lake at a volcano.
