Question about the maths behind attack roll and defense rolls

[Anthony]

Originally Posted by Kromm

GURPS is nifty in that even during prolonged exchanges where nobody loses HP, there are thrills and chills when the fighters' choices lead to near things (like making that Parry roll of 9 exactly when somebody swings an axe for your neck), and plenty of nondamaging effects: feints, FP spent on extra effort, falls (esp. during kicks), dropped or broken weapons, ground lost to someone whose attacks demand retreats and who always steps after attacking, etc.

Though those effects tend to be either fight-ending or extremely transient. In general, the advantage of a hit point system is that it makes combat relatively predictable (you don't have people flattened by a single bad roll, and a GM can know that a specific fight is highly likely to be challenging but beatable) and means you can pretty much tell you're winning (or losing) before anything too dire has happened (and, if you're losing, perhaps break out your Special Tricks, or whatever).

This isn't realistic -- realistically, random bad luck gets people killed in combat all the time -- but IME players don't really want realism.