Personally, I'd put this slightly behind "team" sports because it often lacks the element of bonding and being part of something bigger than oneself.
That being said, some kids prefer competing with themselves than with others, and if thats their niche, it should be encouraged. As in all things, however, the parent should examine their own motives. The kid should be doing it because they want to, not because the parent is living vicariously, or hoping for a big payday down the road.