I've wondered if that's because Mac doesn't like to fight. It's like his last resort... he'd much rather come up with a diversion of a different kind. It's sort of like why he'll try to save anyone from dying, even the bad guy... his ethics are just that strong.

I'm pretty sure Mac hates to fight!

But seeing as fighting goes with the territory of his job, if I were him I'd want to be the best fighter I possibly could. While a fight is more often than not an out-of-control situation, a really good fighter can 'steer' the person they're fighting. As a really good fighter, Mac could better control how much damage he does to his opponent and keep it to an effective minimum.
He might also not get battered himself so much!