Punching someone in the head seems like a good strategy but you'll likely break your hand.
Boxers wear hand wraps and gloves. MMA fighters wear gloves.
Boxers have even broken their hands wearing wraps and gloves.
You wear gloves hitting a heavy bag.
This is why the old time karatekas conditioned their hands. The problem with that is turning your hands into clubs messes up your hands.
Even so, the target of a karate punch was usually the solar plexus, a soft target.
Spiers goes after soft targets or uses elbows against the head. Smart.