I'm a bit surprised by this dismissal. Of course some info must be collected, or there must be some cost to enter (probably both I mean phone number is also a cost, but one most people already sunk). But we can still debate the best way, right?

For example:

* Are you absolutely positive signal will never have a bug that let attackers reveal contact phone numbers? I really trust in their secure coding skills, but this class of vulnerabilities (like 2fa leaj) happened to even the biggest players.

* One of the reasons signal collects phone numbers (and asks for a contacts permission) is to check which contracts are already on signal. For some people or in some governments even having a signal account is an opsec problem (to be fair, they have a secure privacy-preserving protocol for this - as you know - and it's possible to avoid this footgun if necessary)