The second I went to sign up and learned a phone number was absolutely required, I knew that their privacy was pure bullshit. That little declaration at the end here is an absolute slap to the face.
It’s bad for privacy no matter how you sell it. Unless you have a good amount of disposable income to buy up burner numbers all the time, a phone number tends to be incredibly identifying. So if a government agency comes along saying “Hey, we know this account sent this message and you have to give us everything you have about this account,” for the average person, it doesn’t end up being that different than having given them your full id.
Another aspect is the social graph. It’s targeted for normies to easily switch to.
Very few people want to install a communication app, open the compose screen for the first time, and be met by an empty list of who they can communicate with.
https://signal.org/blog/private-contact-discovery/
By using phone numbers, you can message your friends without needing to have them all register usernames and tell them to you. It also means Signal doesn’t need to keep a copy of your contact list on their servers, everyone has their local contact list.
This means private messages for loads of people, their goal.
Hey, we know this account sent this message and you have to give us everything you have about this account
It’s a bit backwards, since your account is your phone number, the agency would be asking “give us everything you have from this number”. They’ve already IDed you at that point.
Guys like you see privacy as a monolith, that it never is. Unusable privacy is meanigless as email had shown. Privacy of communications does not mean privacy of communicators and usable authentication can be more important then anonymity.
And all this has to be realised on real-world servers, that are always in reach of real world goverment.