If it worked that way, powerlifters would just stand with teh bar straight up over their heads during training, never lifting. if you do pushups on youtr palms your working the muscle required to hold you at a 180' angle to your body. thats why i think its best to be able to do both
I'm not saying knuckle pushups will make your arms stronger than doing palm pushups. I'm merely saying that it helps train the wrist to be solid during a punch. The last thing you want is for your wrist to buckle during a punch. It should be solid, as if there weren't even a joint at the wrist. If you squeeze your fist while doing the pushups, you will notice it does work the forearms. I understand the palm pushups work well, although differently. During a knuckle pushup, the forearms are working to support the wrist. It is of course a static contraction, but it trains the wrist to be solid during the punch. That's the only thing I'm claiming is better about knuckle pushups.