For example, Germany requires registration of burner phones with ID or passport before any network is allowed to activate the SIM. The ID and passport obviously are linked to your fingerprints and face.
Signal is advertised to people in oppressive regimes as a solution to avoid the government from snooping on their messages (this security from nation states is further implied due to their framing of Snowden comments).
Requiring an identifier that’s linked to a government ID is the opposite of that.