I'm still not buying what HP represents. And yes, I know, its pretty much always been this way in D&D.
Their example... A Fighter with 10 hit points gets bit by a spider for 3 damage. Barely a hit, but just enough so he has to make a fort save vs the poison. So what happens when that same spider hits that same fighter 10 levels later? When the fighter has 60 hit points. If 3 hit points off of 10 is a "near miss" then what is 3 hit points off of 60? The fighter has to make a saving throw.
How about an arrow attack? An arrow hits the Fighter for 3 damage. Realistically, you get hit with an arrow, you're as good as dead. But this is D&D, and not all is as it seems when hit points come into play. According to how D&D views hit points, this might not be a hit at all. Maybe you dodge out of the way, or luck came into play. You exert some stamina for getting out of the way in time, and this is represented by taking off 3 hit points from your total. But what if the arrow is poisoned? Now you have to make a save. So if the arrow missed you, it didn't really miss you.
What about falling 100 feet? Using current D&D math, thats 10d6 damage or 30 damage on average. The 10 hit point fighter goes splat (reasonable) but the 60 hit point fighter somehow 'bouces' off the ground with maybe a few bruises?
I know Hit Points is the best we have, but they really do not make sense in a lot of cases. Its just one of those things I try not to think about too much.