Building power in the gym means moving weight fast to recruit the most motor units possible. The hang snatch, a variation of an Olympic lift, is one of the best explosive power movements.
In terms of power output, the snatch matches the clean closely. The snatch may be heavy on technique, but once you get the "hang" of it (after some serious coaching, I hope), you'll find its power-creating potential to be unparalleled; power that carries over to the rest of the weightroom. I've never met an athlete that's strong enough to snatch 225-pounds that couldn't squat, clean, and bench with the strongest carnivores in the gym.
It's much easier to achieve a respectable start position from the hang than it is from the floor. The snatch from the floor takes a ton of mobility at both the hips and ankles, and for many athletes this is an area that requires a serious intervention.