Privacy ≠ anonymity

Because they're building a private, not anonymous, instant messenger. They've been very open about this.

0. Yes, and in that time you would visit a website with your own IP address likely, likely over HTTP without SSL/TLS, likely with your vulnerable browser fingerprint. Point?

1. Privacy, not anonymity. Two completely different things.

2. Because the way Signal is built hosting it requires a lot of resources (storage especially), so they want spam prevention and fewer accounts per person.

https://jami.net/

Offers the same privacy but is not centralised. it's peer to peer

Spam prevention

Everything is a balancing act. Privacy, anonymity, and security aren't the same things. They're sometimes, and in some aspects always, difficult to achieve without compromising one of the other two.

When you add in the goal of quick, easy setup to make the service useful in the first place. Doesn't matter how good the service is at the trinity if nobody is willing to use it. Signal just errs on security first, privacy second, anonymity third.

SimpleX

Bots. If it makes you feel better, you can disable other people finding you via phone number and just give them your username. All messages are private.

as I see it, Signal tried to fit that privacy gap for a standard centralised messenger, if you think about it, that might have made it easier to non-tech-savvy people to adopt it (even if it was as a request from a contact), decentralisation is not remotely appealing to them