> If your so-called friends don't have your email address, they aren't your friends.
I don't think that's fair to say in 2020. I'm not arguing for facebook's goodness here, just its ubiquity. When it comes time for me to organize a friends-only event (i.e., not a meetup or community event), I'm not aware of anything better than FB for the task. Say a party with 50 people at it - not all those people have my phone number or email address, but we're still close enough that I could tell you where they grew up. Maybe we chat on messenger sometimes.
I'm actively looking for alternatives. I think I'll disable my FB to still have access to messenger, but mostly I need a replacement for Events. Marketplace is pointless - I get way more hits on my craigslist posts anyway. Photos is stupid, I just put my stuff on photos.google.com and share the URL with people. Hah, though I am just now remembering Instagram is owned by FB.