But the ribbing or texture serves an actual purpose, so it's not quite skeuomorphic. It's not pure ornamental.
Where it exists at all. Most knives you'll actually encounter aren't ribbed at all. There are lots of ways to provide grip and all of them are used.
The crazy thing is, you gave a perfectly good definition of skeuomorphism, then keep using the word in a different and sillier way. You're doing the same thing you accuse the video of.