My FB was becoming a ghost town 5 years ago, so I stopped using it, then deleted my "real" profile. I maintain a shell account now for Marketplace, Groups, and Messenger. I have the "light" apps on my phone with all requested permissions denied.
Marketplace SUCKS from a usability perspective, but it's become equally as active than CL in my area.
Groups are a goldmine of information - my neighborhood has one that is active, I have an active one for my model vehicle, and there are B/S/T groups that are nice, as well. Groups have effectively killed the old Forums/Bulletin Boards.
Messenger is required if you want to buy/sell, etc. I don't use it for anything useful.
There's extra financial value in knowing who is attracted to whom.
I cannot imagine just how terrible the privacy must be for people dating via Facebook.