Think of dwarven giant fighting tactics. The axe was used to sever the tendons behind the knee while the hammer destroyed the kneecap. The giant falls to the ground and is swarmed by dwarves.
In this case HP damage might be less than a measure of physical toughness but more a case of tactical points to defeat a monster. In other words the majority of the actual damage comes later but the earlier damage has more of an impact on setting it up.
I agree, a dwarf fighter with full attack can do some serious damage if the character is willing to take the dragon's hits..l