For Tabletop, hitpoints are just there to make GMs' lives easier. Personally, I haven't used them in several years. A good GM doesn't need them. Videogames are a whole other story though. Because of the inherent lack of freedom presented in video games, the player doesn't have the options and resources open to them to circumvent injured limbs and body parts that they do in a tabletop RPG, where your imagination is the limit. Some games do use limb hit detection and dismemberment. Die by the Sword, an old PC game, did this to great effect. Each body part did have it's own HP total though. And some more cinematic games like Heavy Rain seem to be able to pull it off. It's frustrating to have control of your character hindered or gimped in videogames for a long list of reasons that any veteran gamer would know. More than I feel like listing and explaining. It's common knowledge to programmers that the vast majority of player's like consistency in their controls and hate any loss there of.