Earlier quoted context omitted.
And Signal forces you to use your phone number as your identifier, which can be traced relatively easily to a person or at least a geographical position by the authorities. The content of the message might be encrypted, but metadata can provide valuable intelligence insights. At least Matrix can be used mostly anonymously through a user-generated identifier, without an email address or phone number, and can be used t…
I recently changed my mind on this: being able to use phone numbers as identifiers also has some benefits: Last time I was on vacation, it was easy to get in touch with service providers (e.g. surf school, massage place) via WhatsApp, simply because I had their number, and everyone used WhatsApp anyways. If Signal would be more popular, I could instead contact them directly via Signal, since I only need their phone n…
The most common client, Element, will by default ask you for your phone number when registering with the default matrix.org homeserver and the default vector.im identity server will associate your phone number with your matrix user.
So by default (changing servers and/or opting out is easy and encouraged BTW), Matrix already works like you would prefer.
This is BTW a main critique in the OP since it makes vector.im a PII and metadata aggregator.