I find switch riding to be extremely helpful for developing symmetrical strength and reducing the impact that many riding consecutive riding days has on the body. Riding one way all the time develops strength, flexibility, and puts general wear on your body in some unexpected ways. Riding switch frequently helps to alleviate some of those effects.
As a personal example, I happened to visit a foot and ankle doctor recently for something unrelated, and after some x-rays he asked me if I leaned on my left foot a lot. Which, of course as a regular rider, I lean on my front foot constantly. It turns out that the bones in my left foot are now aligned differently than the bones in my right foot, solely from riding regular for so long.