[1 attack roll] is not =to [1 swing of a weapon].
A creature that makes 3 attack rolls against one target might only make one mighty swing. The inverse is also true; a creature that makes a single attack roll, might be stabbing his target multiple times.
Same deal how a 'hit' with an attack roll, doesnt necessarily mean you actually strike your target with your weapon. They could dodge or parry the blow at the last second (losing 'hit points' and tiring) or the blow could be luckily deflected (losing 'hit points' and running out of luck).
'Attack rolls' and 'hit points' are all mechanical abstractions. How they're narrated is entirely up to the group.
Some of the heavy facetiousness inherent in my post may have been lost. But this is exactly my point: the mechanics are all abstractions. It's a game. Trying to bring in too much simulationism is counterproductive, IMO.