>>371505514
that's not even remotely true!
box colliders use some very fast math (AABB) to check for collisions, and you can use a shitton of them with zero performance issues (especially if they're on static objects and therefore not on a rigidbody).
meanwhile, non-convex mesh colliders have to manually check for collision with literally EVERY SINGLE TRI in the mesh, as long as the player is inside the "bounds" of the mesh collider. this problem is greatly lessened with convex mesh colliders but those can only be, well, convex.
it's kinda like how a sphere collider is just (if distance <= radius). Box colliders have similar fast math available to them, as do capsule colliders.
meanwhile, a 500 tris mesh collider will have to run all of its calculations 500 times.