I agree. IMO, the kids who are serious about MA must have a strong stimulus to do it. That stimulus could be real physical dangers, through bullying, threat of crime, etc.; or simply wanting to change from weak/afraid to strong/confident.
Any health benefits would be a natural side effect of training, not necessarily a good reason in and of itself to train MA. If that's the main reason, someone could have faster and more specific results going to a gym or yoga class.
As for self-cultivation, I used to think so, but never really understood what it meant in relation to MA. One of the most talented MAists I ever met was a 50-year-old career criminal overseas. I haven't really noticed any correlation between MA and building better character. Those MAists who have better character (and I've known a lot of them, too) are that way because they are more mature, evolved human beings, and probably would have become that way anyway, without MA training. If hard physical training made better people, then all elite athletes should be saints, but we all know that's not true, not by a long shot.