Hit points are a weird leftover from 80s games

Darkfall
Even in new releases like Darkfall, hit points still decide when you die

Why is it that after 25 years, the enduring mechanic for modelling player damage in computer games is the hit point? We have virtually photo-realistic graphics and animation now, but injury or lack of same is always represented as a single number. A homogeneous pool of life or health or hit points where any number greater than zero represents total combat effectiveness and zero means instant death.

We have games that separately track damage to each of your weapons and armour, games that allow you to rip off an NPC opponent's arm or leg and club him to death with it and games that allow for complex and imaginatively named combo moves to be chained together. But in the end, victory just comes down to whittling his number down to zero before yours.