ManAs some older martial artists have said in interviews, to be strong, is aptly answered. But, I think that speaks to a lot of people who study a martial art. Are there other motivations than that?
Well sure. There's status, wannabelieve-something-esoteric, social, ritual, pecking-order, and a number of other reasons. Generally speaking (i.e., there are exceptions) some of the nicest martial artists (true Wu-De/Bu-Do) I've met tend to be the ones who are purists and always looking, regardless of the other stuff. There's a common feeling that is usually pretty recognizable.