In fact, some people hike into canyons. You keep going until you get to the river. Sort of an inverse top. It feels good to be up looking down. You don't feel the world is pressing down on you.
Military strategy is to take the high points.
Good visibility, and saps the energy of attackers coming up. So we feel more secure on top. If you want to find out more about hillwalking, hiking, or mountains generally you could start by learning some of the necessary buzz words . . .