Many of us are reluctant users. There because our friends our communities are. I would love FB to go away.
I am the admin of two FB groups, both UK home education related (one about exams and qualifications, the other for single parents). I do it because I feel I should help the community (especially as the crappy commercial groups that target the same audience), which is made up of non-technically inclined, mostly middle aged women - i.e. FB's core demographic. I cannot remember the other demographic nos offhand, but its 95% women in the exams group, and 98% in the other (and both have 1% other/did not say), and the age profile reflects the fact that people have school age (or just over, in the 16 to 18 age group) children.
I had actually planned to try and push the community towards forums, but with the Online Safety Act in force that is not a risk I am inclined to take.
My cousin runs a family group where she shares photos and wishes people happy birthday. I would prefer her to use WhatsApp but she is the one running it.
A lot of my friends post family news, important things like births and deaths and weddings on FB.