Everything boils down to the thread model.

Not everyone is paranoid at extremum.

> PGP has no forward secrecy and OTR in XMPP lacks future secrecy, multi-device support etc.

Have you ever considered that perfect-forward-secrecy is not needed by 99% of the people? And PGP (OX) can be enough of encryption that gives you multi-device support.

Btw. OTR is long dead…