Facebook (if you don't use newsfeed) is a very useful product.

Local events - check

Local groups - check

Small time music bands/artist/performances/etc - check

Buy nothing groups where I can get rid of something I don't use - check

Groups for mom with kids to get organized for some kids event - check

A library having a read together event for a kids book author - check

I'm happy I don't have to use FB, but my wife uses it all the time, she just avoids newsfeeds and all the click/rage bait parts.