Have you ever heard of a fighter named Mirko Filipovic? He follows the same logic of thinking when it comes to his kicks. Instead of spreading the damage out over the entire width of his foot, he concentrates it on the tip of his big toe. All the damage is concentrated into a "spike" if you will, bruising internal organs. The same principle is applied to the Gentle Fist Technique. Shrink the area of contact and you increase the damage internally. And just so you will all shut up a palm strike does have less impact zone than a fist strike, thus causeing more damage internally.
Fist strike, palm strike, knuckle strike, fingertip strike. In that decending order is the impact zone of hand strikes.