Is friction usefull in playgrounds

Friction is fascinating because in so many situations we try to reduce friction, but friction is a necessary force, without which everything would be impossible. Without friction we would all be flat on the floor without any methods of directing our motion. We would randomly collide with things and then continuing moving in another direction. Without friction the slide at the playground would be really fast, but you could never climb the ladder to get on it. The swings would be useless since no one could get into them.

So friction is necessary for playgrounds.