Of course! It gives them physical exercise and gets them away from video games off the couch and teaches them discipline (something lacking in today's child rearing).
Karate teaches self defense in case you ever need it but it teaches to never start a fight and i have seen it personally change many young men's attitudes and gave them confidence they formally didn't have. Fighting is a great skill to have because these days you better be willing to fight for what you believe in or get trampled.