Comment by GuB-42

They also blew up because it was also quite decent SMS app, so you just had to install Signal and use it instead of your default SMS app. All your messages are there, you can continue to communicate exactly like you did before, except that now, if the other person also has Signal, your messages are encrypted.

They stopped doing that (and I uninstalled Signal as a result), so they can also stop with the phone number thing, in fact, it would make more sense than with the current situation where Signal needs a phone number but doesn't use it (except for registration). I could even reinstall Signal if they do this.