first of all, ANY form of exercise would be GREAT. Gymnastics would be great too.
For me, yoga makes me feel very energized and refreshed, in ways which sport does not. I feel a lot healthier when I do it regularly. and i think the key difference (supposedly anyway, as I haven’t tried everything else to be able to personally testify) is that yoga really helps you calm your mind, and is designed in a way as to promote the entire energy flow within your body (if you believe in that sort of thing).
Ultimately, yoga (asana) practice is designed to help promote meditation, which is meant to be one of the keys to spiritual growth (whatever your religion, if any).