Well, reading through this thread I'm not even totally sure what we're talking about except that it has something to do with sharpening knives. I will not work with dull tools, but I know there are different types of edges you need for different types of work. If you're going to cut meat you will do better if the edge is ragged on a microscopic level. If you strop your knife with a smooth bar of steel you'll have a bur that does the cutting. If you smash a chunk of obsidian or chert, you'll have a rough sharp crystalline edge that will cut. That same edge will not hold up to woodworking chores, one of the final things some people do with a woodworking blade is make one pass with the finest stone, right across the edge. Squares it off a little bit. That actually works better than a razor sharp edge but it isn't a butcher's tool. I'm not sure about what it takes to cut hair, I quit cutting mine in the early 90's when it started moving to the back of head anyway.

That thing about fast healing makes sense to me, one of the old surgeon's tricks from the Civil War days was to cut a slash through a bullet wound, a straight cut heals faster than a hole. Rough edges make sense in the same way, increases the surface area of the cut.

Velocity counts. I was whittling a piece of wood in the early 70's with a razor sharp knife, which slipped. Sent the tip of one finger flying across the room. Fortunately, just a little bit of it, it healed up ok. There was no argument about edge efficiency, it just went sailing away.

JimmyTH