As a content creator you’d have to be window-licking mad to sign up to Facebook’s planned fan subscription model.
Amongst the truck-load of things wrong with it, you give Facecbook:
Non-exclusive, transferable, sub-licensable, royalty-free, worldwide license to use [creators’ content]
This license survives even if you stop using Fan Subscriptions.
Which essentially says Facebook has control of your content now and forever more.
On top of which they can take up to 30% of creators’ royalties.
Facebook is trying to compete with Patreon (which, incidentally, only takes 5% of your royalties) and Patreon do indeed have similar terms to the ones Facebook propose. There are differences, though. Patreon is a dedicated platform for this sort of stuff. Facebook isn’t and it has a poor reputation when it comes to data, content and the treatment of creators, as recent scandals have demonstrated.