[granos]

When you (or the recipient) don't want the recipient to be able to read the data, but only to store/transfer it somewhere.

In some cases its impossibly/impractical to create a direct connection between 2 computers: you must use some kind of relay. If you don't want the relay to comprehend the data then you can use client side crypto on the payload. TLS still matters because it prevents 3rd parties from peeking at the communication.

Imagine a secure chat app where you want to guarantee that only you and your friend can read the communications, but want to be able to send offline messages to each other that get delivered upon connection.