Maybe this is a case where geek interests and casual interests converge. Some people may literally be doing for chicks. Personally, I'm about to start because a) I want to be healthier (= longer life and better life quality in old age) and stronger (= more capabilities), and b) because it's efficient. I have shit ton of things I'd love to do in little time that's left after dealing with work and other people, so I want to minimize time spent on things that I don't care about per se, but only seek their outcomes.

Oh, and c), I heard it helps with depression.