From internal leaks within the company as well as external analysis, the tip of the iceberg behind Facebook's spyware empire is exposed. Take a look to better protect yourself when you're not even on the platform: https://simplifiedprivacy.com/facebooks-corrupt-off-platform-surveillance/
I know these are there - I said so in my post. It does not work when others are on FB and will/can not leave for another platform. None of that is comparable to to FB for group chat, looking for people, swapping pics etc. People may not want their phone number given out (a bit ironic when FB has everything else I know).
It's so easy (and dare I say lazy?) to just say 'FB bad, use phone/Signal/email etc.' but not offer any real alternatives. Let's face it, FB has this covered. It's so simple to get your nan, mate to join because all their friends/relatives/workmates are on it. There's no shame in admitting that it provides a valuable service for some people.