It's also just a game where the focus is supposed to be on roleplaying. If taking into account injuries using a simple system that doesn't require more character sheet space, or GM tracking, can be used to enhance that roleplaying (even if it's as simple as aiding the GM in providing more vivid and interesting descriptions), then it's fine with me.
Now if your group is all about using the rules to simulate as much about combat as possible, then obviously you'd want to make sure every little thing has a mechanical impact. Scars that give penalties or bonuses to charisma checks, gimped legs that reduce movement, poor vision, bad hearing, the crabs, lice, etc, all have a place in a game where that's important stuff to track.
I just don't think D&D is anywhere close to that, and I offered a suggestion for handling magical healing that can enhance the game and not change it so drastically with all the complexity that comes with injury systems.