[rvba]

What is good about signal? It does not allow unique account names (!), but uses telephone numbers - what is just absurdly bad security.

The state can make a duplicate of your sim at any time. Not to mention linking phones to people is relatively easy.

[qilo]

Signal introduced usernames about a month ago.

https://signal.org/blog/phone-number-privacy-usernames/

[margorczynski]

Complete E2E encryption, only you and the person that you're talking to can read the messages. Yes, having you be identified by phone number is not great but they introduced usernames recently.