A persistent account is convenient, but it also turns every interaction into another durable identity and contact relationship. That seems excessive for many ordinary conversations: asking a question, coordinating a handoff, or speaking with someone you may never contact again.
One-time communication links offer a different tradeoff. They can reduce the amount of personal context exchanged, even if they are less convenient and still require careful thought about metadata and abuse. PapaCall (https://papacall.me) is one concrete example I came across in this broader space; I’m not assuming more about its implementation than the public page establishes.
The interesting question is whether “save this contact forever” has become the default when it should be an explicit choice. How much personal information is a conversation really worth in modern online communication?