No, tape recorders are not part of the normal operation of phone networks.
The point is that even if a user intends to have an ephemeral conversation over an internet service all kind of middle-boxes may keep more persistent copies.
Something that normally does not happen with either face to face or telephone conversations.
With unencrypted digital communication on the other hand past conversations can be dredged up from all kinds of places.
End-to-end encryption basically abstracts ephemeral communication over channels with some sort of persistence.
The point is that even if a user intends to have an ephemeral conversation over an internet service all kind of middle-boxes may keep more persistent copies.
Something that normally does not happen with either face to face or telephone conversations.
With unencrypted digital communication on the other hand past conversations can be dredged up from all kinds of places.
End-to-end encryption basically abstracts ephemeral communication over channels with some sort of persistence.