In addition to examining the genre implications of hit points, we should also think about the implications of healing. Because maybe getting shot and simply having your hit points lowered from 64 to 56 would be a big deal if healing that damage was impractical. Like, imagine there was no cure wounds and a short rest took a week and a long rest took three months, or something ridiculous. So over the course of an adventure, your HP would gradually decrease, and the effective "danger level" would ramp up. Yes, you can charge in recklessly during the early encounters since you know you won't die, but then you're wasting a really precious resource. Or, maybe you heal automatically whenever you do something suitably heroic. So now, managing your HP as a resource introduces an interesting trade-off -- the reckless charge might get you some damage, but it might also get you some healing... How do you like them odds, cowboy?