[fauigerzigerk]

How does the phone number tie-in make it usable? Phone numbers and SIM cards are about the most user hostile thing I can possibly think of.

What's wrong with the way Threema does it for instance, which is essentially to bind the identity to a key pair that you can back up?

[LamaOfRuin]

Threema appears to optionally do the exact same thing. Signal eschews the flexibility to ensure more universal usability by being able to assume that anyone who uses signal can be associated with their phone number. An assumption that holds for the vast vast majority of potential users.

[fauigerzigerk]

I don't see how making phone numbers mandatory makes Signal easier to use at all. There must be another reason for this restriction. Some say it's for spam protection.