The fact that I pulled my statement from the netherworld is completely irrelevant. No self-respecting swordsman would default to a DF in a fight. He would, of course, resort to the use of his blade(s). Sure, Law can swing the actual sword at people, and can make hacking motions that would likely cut an opponent if they got in the way. But he's a far ways away from having a duel with Zoro. Or Shiliew. Etc.