It seems useless to me, at least regarding the cybersecurity aspect. Of course, it's helpful when people ask for my contact information, and I don't want to share my phone number or email address.
But they still require information that could be used to prove or be linked to my identity for registration, right?
This means a hacker could still reveal your IP address, phone number, email, and your passcode. Likewise, the development team can access these as well.
I know I'm overly cautious about my privacy, but that's just how I am.
All the personal information you mentioned should be hashed or encrypted. For any given phone number, see how little information they have: just an account creation timestamp and a last access timestamp.
There's so much FUD about Signal it's ridiculous. I'm starting to believe those glowie memes are true it's just the "lol like I'd ever trust Signal!!!" folks who I think might be the glowies. 🫣🫣🫣
spoiler
(No I don't actually believe they're glowies lol).
My main complaint is that they officially prohibit 3rd party clients including 3rd party builds of their official ones. They also don’t have reproducible builds for their clients. It leaves the door wide open for inserting some telemetry via an update to completely bypass their otherwise good encryption and (lack of) data retention.
They can already do that. You can make custom clients that pretend to be the real one, it’s just against their terms of service. Spammers generally don’t care about the ToS though, so it’s just legitimate users that are affected.