Actually, that works *really* well. I've never seen anyone win a fight after a swift snap kick to the family jewels.
Seriously, if you wanna go around fighting people using the weakest half of your body, go nuts. But being able to throw your whole body weight behind a well placed roundhouse kick or flying kick of death (whatever they call that one) is actually pretty useful. I seriously doubt you're one of those meat heads who can bench press his own body weight... but you have to have seriously weak legs if you can't leg press a lot more than your body weight.
Well, or at least do it right and buy a riot baton or a gun something. It's just pathetically inefficient to go around hospitalizing people with your bare hands (or feet).