Most games measure the physical status of characters with a linear number or bar, which typically measures their status from perfectly fine to dead. Whether it's called hit points, health bar, or life, damaging effects will reduce it by flat, cumulative quantities that can end in death from a thousand paper cuts just as effectively as an explosion by their head. This made sense at one point, but in the current wider context it's nonsense.
The origin of roleplaying games, as well as a shocking number of game design conventions, is Dungeons & Dragons, often abbreviated to D&D. It was adapted from Chainmail, a medieval fantasy wargame in which most units would die if hit by any attack. When adapting it from a wargame to a roleplaying game, Dave Arneson wanted to increase survivability and granularity so that players would feel more like heroes than expendable soldiers. He added in the 'hit points,' which presumably represent an individuals physical health, as well as dodging skill and luck to some degree.
These hit points were based on civil war naval combat wargames, in which ships would have hull points that were depleted by attacks before the ship would sink. Much like the infamous one-minute combat round, hull points made much more sense in their strategic origin than they do in a more specific, individual scenario. In both systems, the target is fully capable of fighting and moving at full potential until defeated, being either sunk or killed respectively. When a ship is taking shots to the hull, it makes sense that the guns would be fully capable of firing as long as the ship stays afloat, barring possible crew deaths and direct hits to the weaponry. But when a person is wounded significantly, they are noticeably less capable of wielding a weapon or defending themselves, even while alive and still able to fully recover later.
The issue here is that damage and wounds are tracked in a purely linear, cumulative manner. Some games will actually include specific types of wounds, but they usually take the form of a very restricted and oftentimes minor debuff caused by one special attack. Consider some real world comparisons. If you have ten paper cuts along your hand, each one centimeter long and one millimeter deep, then that wouldn't matter much. If instead, you had one cut ten centimeters long (about four inches) and one centimeter deep, it would be significantly more concerning. And likewise if you had ten of those cuts, they would be nothing compared to one wound a meter long (about three feet), and ten centimeters deep, which would be a mortal danger no matter where it is on the body.
In this consideration it seems quite obvious that most wounds on a human don't quite add up in the way hull damage does on a ship. It can be a helpful simplification in a tabletop game, or in early computer games where processing power was limited and detailed simulations were difficult. However, for any modern video game trying to claim any realism, a health bar or life bar of any kind really makes no sense. Many games, such as most military shooters, try to make this seem more realistic by hiding the health bar, instead displaying blood effects on the edges of the screen and allowing health to regenerate over time.
In fact, this quick health regeneration makes the health system significantly less realistic, and accomplishes only a more even balance for a game with guns and attacks that can't be dodged reliably. While there is an argument to be made for this balancing, my point is that an argument could equally be made against the general concept of linear health bars. For tabletop games, adding a complex wound system always bears the possibility of making the game overly complicated and unwieldy, but there are better ways to handle that as well. And making players worry about every wound will increase the tension of the game, creating more engagement and interest in the outcome of every conflict, and in turn increases the sense of reward whenever a challenge is overcome.
