> Secondly, it needs a phone number all the time to use, which ties in with personal identity. Why? A better alternative would be a project that allows someone to choose a username and be done with it! Like HN!

Thousand times this! And it is actually a problem both with Signal and Telegram. In the latter case, I managed to avoid installing Telegram app on the phone, by using Android emulator and registering from that, but why forcing users to use such workarounds, instead of simply allowing to register without any ties to the telephone. I'd be willing to pay for a messenger which provides privacy and is not tied to the phone.