Waste of time? I guess it depends on what you want to do. For self defense, I'd say a properly executed kick would be more devastating to a would be attacker than a punch in most cases.

I saw a K-1 match the other night on ESPN, and I have to say, that if that winner from that match got into the ring with any boxer I've ever seen he would have given just about any boxer a run for his money. The fight was over in about 60 seconds and he was fighting a veteran with an impressive record.