Not beating the NSA collection allegations. I get the excuse is that it stops spammers but in practice it also ties each account to a payment transaction tied to a real human person just the same as a phone number which allows the NSA and other eyes groups to do metadata graphing analysis on who you're talking to, when you're talking, how much you're talking, etc.

Even presuming they don't have an NSL in place and NSA devices on their servers reading everything sent via their Google and Apple distributed apps (no way to prove those apps properly implement e2e and reflect open source code published and a big if given their founder and board are under US legal jurisdiction) this basically gives NSA/GCHQ/eyes agreement countries 90% of what they want in that it ties a real person to the account.

Signal is still preferable to getting zucked by Meta alternatives or Discord obviously but I hope no one truly thinks it's actually high confidence private from national security organs given all the weirdness.