Nobody asked for spaced repetition nagging, and no way to turn it off. its so condescending and stupid of them. If you don't give users a choice, the only choice left to them is to stop using your app.

Yeah, maybe they could leave an option to disable this. But it takes like 30 seconds to input your pin if it's really long, and that's every few days. I for one think it's a neat solution of "now give us an 8-digit pin you've set up a year ago" problem.

these are not user profiles, this is cloud backup of your contacts and settings

if it was trade off that together with PIN I can start using Signal without phone number on devices without SIM I would be much more understanding

Which I assume is a first step towards user profiles. Their development team is small and every feature has to be implemented using state of the art crypto.