For me it's not about blackmail, it's about making sure the camera isn't accidentality enabled unexpectedly during a meeting.
The worst that would happen is I'd look kinda unprofessional slurping up some noodles, but having the camera covered allows me to be confident I'm not presenting unless I intend to.
We've been 100% Microsoft Teams since March so I'd say that in several hundred calls and conferences since then I've never activated the webcam without intent.
It doesn’t matter how often this happens, it matters that it can happen. It is much nicer to have a cover and not worry, then to always remember “did I remember to deactivate the camera?”
The worst that would happen is I'd look kinda unprofessional slurping up some noodles, but having the camera covered allows me to be confident I'm not presenting unless I intend to.