[fabiom]

> If you send me a message, I can prove to anyone in the world that you sent me the message.

Only if you sign the message, right? But you can use PGP to send encrypted messages without signing them.

[cyphar]

And then if the message is corrupted you have know way of knowing. Not to mention that essentially nobody uses those modes.

Axolotl and OTR provide signatures, just that they are "non-transferrable" (so to speak). Not to mention that the actual crypto is more modern.