I’ve moved across the country a couple of times now. I’ve lived in 5 different states and have contacts and friends around the country. (And some outside of the US). Facebook, when it allows me to see someone’s new marriage, their kids, or even the sad things they are living with, provides the best way I’ve found to at least keep in touch in some small way with a lot of those folks.
It’s all the other stuff that makes Facebook terrible.