They're already working on it: https://www.bleepingcomputer.com/news/software/signal-tests-...

Not whether that's a good idea is more debatable; you're not wrong about discoverability.

They also blew up because it was also quite decent SMS app, so you just had to install Signal and use it instead of your default SMS app. All your messages are there, you can continue to communicate exactly like you did before, except that now, if the other person also has Signal, your messages are encrypted.

They stopped doing that (and I uninstalled Signal as a result), so they can also stop with the phone number thing, in fact, it would make more sense than with the current situation where Signal needs a phone number but doesn't use it (except for registration). I could even reinstall Signal if they do this.

Why not both?

If I want discoverability, let me provide my phone number.

If I want privacy, just assign a random identifier.

Nobody is demanding them to stop supporting phone numbers as identifiers/verification methods.

I'm not mad at all if somebody prefers using their phone number and not having a password for a service – just give me the option to use my email address and/or a username.

There are too many "phone number only" services out there these days.

It has nothing to do with friction...

Getting rid of phone numbers would make anonymity easier, but it wouldn't affect privacy. Signal is explicitly private but not anonymous.

In most countries, you can get an anonymous phone number anyway.

If only it was possible for a service to support both!