I watch them, just mostly on mute. They're good for multiple angles, see the action, get an idea of size in hand.
Don't care about the opinions one way or another really. I do appreciate the reviewers who do more than could've been done with still images and an article though. I think some reviewers ought to try watching their video on mute as well to get a sense of whether they made a video or really just a few pictures and narration. If the video is about the knife and not you talking, there shouldn't be a 5+ minute still shot (just my opinion).