I swing a sword at someone while fighting them and within my striking distance, unless they move I will hit them (sword, shield, armor, flesh, what-have-you). Looking at damage in games as I take damage so I'm getting cut I think is very narrow. When I spar with swords many blows land on my blade and I do feel them, after a long enough time I would tire from them and be "defeated." Cuts also pass through my shirt, nick me, or do superficial harm against me as I take "damage." A solid blow to the torso however is very much a critical hit and would likely kill me if I wasn't using training swords. I can't say how the percentages are but unless I parry or evade a blow that I take on my sword does fatigue me a little so their system makes sense in more than just visual aesthetics.