Based on the recipe, it seems that the intended result here is for a denser, chewier cookie.If you were able to perform this percussive therapy maneuver in exactly the method desired by the recipe-writer, then yes, it would knock some of the air out of the cookie, and collapse it's structure a bit. I think that this maneuver would be difficult to perform precisely and repeatedly. Also, you'll have lots of variation in cooking time, as you have to open the oven halfway-though and let lot's of the warm air out of it.
Instead of the "bang", I'd just introduce less air into the cookies during the initial preparation. I think the easiest thing to do would be to under-cream the butter, peanut butter and sugar.