Yeah, it’s certainly problematic, and I’d very much prefer that it not have that dependency. But I think it’s still worth using Signal despite needing a number, because it’s a really low barrier to getting new users on it.
If you want something truly private w/o the dependency on a number, there are better options, such as SimpleX. However, the barrier to entry there is a bit higher.
I have a few problems with Simplex (I worry about it being effectively centralized for now and that the VC funding may get it to either enshittify or stop development)… But I do use it quite a bit and even have the servers (which were very easy to set up and don’t consume a lot of resources). I like a lot of what it does (including being very easy to use), and hope it succeeds as it matures!