Yeah I'm sure that there a some people who are handling the knife with gloves to protect it or imply that it is more valuable, but I also know that there are in fact legitimate reasons to avoid showing your hands.
I remember maybe ten years ago reading about a software that was being used to scan pictures to look for fingerprints that were on the camera lens when the picture was taken. The prints are faint and aren't normally noticeable, but the software could still detect them. Just knowing something like that exists is creepy enough. These days with AI it must be even more advanced. That's why I will never post pictures online with my bare hands, and if I share a photo I am going to wipe the lens before I take the picture. I don't want pictures of my fingerprints being out there. Once it's out there, it's out there and you never know what somebody might do with it later. Technology keeps moving forward.
I know most people never even think about this but maybe they should. Then again, everybody carries a GPS tracking device with a microphone and cameras on them at all times and they hardly give it a second thought. People put all kinds of apps on it and don't even read what kinds of data is being collected. I'm the type who always puts a piece of tape over the camera on my laptop, and I make sure that the cameras on my phone are covered too, until I want to use them.
I consider fingerprints to be private, personal information, and I don't want to share mine on the internet. I know that others feel this way, and some will even refuse to post videos with them speaking. With the AI technology being able to copy someone's voice and make it say whatever you want, it's not unreasonable to avoid posting clips of yourself talking.