Doesn't sharpness demonstrate how explosive the move is from standing still to max speed? It's like car performance measured by 0 to 60, then from high speed braking back to 0. It takes a lot of power to go 0 to 60 under 3sec, and the shorter the stopping distance, the better the brakes are. It's like for about a 3500lbs car, you don't talk about 0 to 60 under 3 seconds unless you talk about 600+hp and AWD to have the power and traction to launch the car.I'll argue that the level of "snappiness" is part of the showiness of the form. It looks and sounds better that way. Power can be delivered with good form without it being that sharp, but it wouldn't look as good in demonstration and competition.
Of cause, that has nothing to do with how hard the girl punch on the heavy bag. This is a form competition, so I just look at the form punching in air.