They don't have to do that because accounts are associated one-to-one with phone numbers.

I don't understand your comment.

Signal doesn't need traffic analysis because it knows the phone numbers of who is communicating.

	▲	echoangle a day ago \| parent [-]
		Traffic analysis isn’t just to identify the peers but also to find patterns in communication (they are telling each other good morning and good night every day, they communicated before a terrorist attack, …)