Don’t confuse privacy with secrecy. I know what you do in the bathroom, but you still close the door. That’s because you want privacy, not secrecy. (From I have nothing to hide. Why should I care about my privacy? : https://medium.com/@FabioAEsteves/i-have-nothing-to-hide-why...)
But privacy is relevant here. Easy example: a person whispering,their private conversation no loses it's privacy due to lip movements being read. Two people enter a room and exchange an item for cash,with radar their transaction loses privacy.
https://medium.com/@FabioAEsteves/i-have-nothing-to-hide-why...