The problem is that you need to own that same phone number permanently. Phone numbers are tied to exactly one SIM card, which is tied to exactly one telco in one country. Too many ties.
Threema doesn't require a phone number but it's not free.
Threema doesn't require a phone number but it's not free.
- [0] https://hitta.se
Perhaps one of the virtual SIM card offerings would work with Signal though.
I'm juggling too many SIM cards and phones already. I don't want any new dependencies that complicate matters further.
I cannot ever let go of the phone number I used to activate Signal. In practice, that means I need to keep paying for a phone tariff I may no longer want.
It is true though that you do need to maintain a phone number. That is one of the trade-offs they made to allow it to actually be usable. I have not seen a better solution for encrypted communication yet.
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?
[Edit] And I think it's essentially the same with WhatsApp, only they now make it a less manual process.