They’d be helpful when interacting with police. Heck, I could see them being useful when interacting with anyone in a hostile situation. What people will say when they don’t think they’re being recorded and what they will say when they know they are can be vastly different, and the people that will speak and act differently are the very ones you want to record. I’ve had occasions in the past where these would have been very useful, though it turned out recorded audio was sufficent.
Unfortunately the tech is ripe for abuse and I understand the mistrust they cause. Too many crappy people, and too many crappy tech companies that will abuse the video themselves even if the person wearing them only used them with good intentions.