I think it would feel good for anyone, but I'm not sure what proportion of people already have it. Anyone who's a natural athlete would have it.

"Coordinated joint mobility" is what I what I came up with to call what my teacher is trying to teach me. I don't know whether it's got a standard name.

The general idea is that skilled movement involves moving at least a little through a lot of joints. If people are unsure of what they're doing, they'll try to simplify the process by moving as few joints as possible. (The Frailty Myth, a book about women and sports, has somewhat on the subject-- there've been studies on how people learn to throw, and it turns out that "throwing like a girl" (throwing from the shoulder instead of involving the whole body) is exactly equivalent to throwing like someone who's unskilled at throwing.)

Feldenkrais Method is very good for preventing some of the effects of aging. The idea is that if you don't use part of your movement repertoire, you forget you have it. Feldenkrais has gentle repeated movements that remind you of your range of possibilities.