Looking at that comparison again, I still don't think there would be a total absense of blood. (is it really perfect, instant cauterization?) I think there would at least be a couple of scattered drops from the initial contact, but whatever. (ok, maybe those drops are out of frame, haha) I just can't help but think about the actual lack of contact time, which I think is a big deal.
We need the Mythbusters to invent a lightsaber and hack up a pig, as the often do. :p