It's also a matter of what sort of information is exposed. Video is something most people care about. Audio, not so much. The latter tends to be far less embarrassing/incriminating.
A camera pointed at my face will, at worst, catch me picking my nose or something. A microphone will pick up all sorts of stuff I really don't want other people hearing. Audio is way worse.
" Haldeman: That the way to handle this now is for us to have Walters call Pat Gray and just say, “Stay the hell out of this…this is ah, business here we don’t want you to go any further on it.” That’s not an unusual development,…
Nixon: Um huh. "