None of these advantages are limited to phone numbers, and apply to nearly any other addressing scheme. Carriers use VoIP systems internally to carry calls, wit

None of these advantages are limited to phone numbers, and apply to nearly any other addressing scheme. Carriers use VoIP systems internally to carry calls, with VoIP URIs mapped onto E.164 numbers via ENUM. Nowadays, the consumer use of phone numbers to dial is a vestigial concession to backwards compatibility at the user-interface level. URIs are better in every respect: they are more flexible, expressive and protocol-agnostic.