Sacred Haven of Debauchery

you need to be able to shoot, move, navigate the map, and anticipate the enemy's actions.

It's the same there, and maybe even more so, especially in shooting, because an arrow doesn't fly across the entire field in a second. That is, you need to calculate, aim, anticipate where the enemy will go, and shoot.
Enemies are usually all in one place, and don't scatter across the map or come out one by one from corridors. And you need more concentration because it's an open battlefield, and danger can come from any direction. While you're aiming at someone in front, cavalry sneaks up from behind and impales you on a spear.