I don't think they imply any sort of mathematical specialness especially. HP are not meat points* (until they are). All the bullets sparking off of railings and making poofs of dust as they hit around the running action hero are hits draining them of hit points, just as all the arrows that hit our adventurers aren't actually sticking out of them like some Frank Miller comic. Its not like a bullet to the head is going to cause significantly more damage that even an average strength man actually hitting you in the head with an arming sword. We seem to have a holy terror of guns that think they are death, but that is only because we do not experience more people getting hit with melee weapons with intent to kill. (and we have unrealistic idea of ability hit targets in the heat of battle with guns)
*Although I have been contrary at times and said HP are meat points and while a commoner gets stuck in the stomach with a knife and bleeds out, a hero can take a broadsword through the sternum and keep fighting. That is just the nature of heroic fantasy. Of course, I've also said that our characters in D&D are not actually human but creatures made of a spongy sort of flesh that gets tougher with experience and not much organs to speak of. Thus why there are no broken bones and other long term injuries in D&D. Then I wax on about how HP are logarithmic which is why only the last one matters.