Strategic Element 2: Simultaneous Action SelectionURL copied
In chess, players alternate. After your move, the board is a known state. Pokémon offers no such luxury.
Both players choose their moves at the same time. Then the game executes them in speed order. This one mechanic changes the entire character of the game.
Not just a flavor detail
Because you commit to your action before seeing your opponent's, the value of any given move is opponent-dependent. There is no "best move in a vacuum" - only best moves in response to what your opponent is doing, which you cannot know.