While I do not consider the one inch punch to be combat useful, it is a good way to get students to understand proper body mechanics for short range punching.

OK, so BL demonstrated the one inch punch all the time, but to say it's not useful in fighting is probably closed minded. I'm not having a dig here, but many people who think they can do it really can't. It should NOT be like a sharp push, it should really whack. When you take a proper boxing straight or hook punch and shorten it to this size, there should be only minimal loss of power. Besides, it is taught not only from one inch. It is more a three inch punch, or just a punch from wherever your hand is at that moment. There are many opportunities for it in a fighting or sparring situation. You should, in fact be able to knock a person clean out with it.
Also, if you learn to make all your punches very short, you will gain a vast amount of speed. I don't nessecarily mean a short distance between your hand and the target, but a small distance your whole body moves, your hand may move up to a distance of about two and a half feet even with the shortest of bodily movements. You ever see those MAists who can knock people out with apparently very little effort, they are using the same principle.
Finally when using it as a straight punch, it's not short range. If you look at the video of Bruce doing it, you will see that his hand is nearly fully extended before the punch is thrown.
No offense to anyone, this is what a forum is for after all, and these are my views. Don't hate the player, hate the game.
Sticks n stones'll break my bones, but if I land the first one, you're in trouble!