I can’t say that I am an expert on the science, but theoretically less finger travel might reduce repeated stress injury. I don’t know if it has been scientifically shown that Colemak helps reduce RSI in comparison to QWERTY.

From my personal experience, Colemak feels significantly more comfortable to type on. When I switch back to QWERTY, I feel like my fingers are all “spidery” in nature, stretching out and crawling all around the keyboard.

The design of the keyboards I type on in general also help improve ergonomics, but regardless if I typed on standard row staggered keyboards I’d still choose Colemak over QWERTY.