Not good enough, you still have metadata, which in this case is gold. "So you were messaging General X, while he was performing the coup. Would you like to tell us more about this, maybe during some waterboarding?"
Email addresses are not necessarily identifiable. Use a VPN or TOR and setup a Gmail account. Or maybe buy a prepay GSM card with 3G bandwidth included, and use it while moving through town.
Have you actually tried to set up an anonymous gmail account recently? Because I think you'll find that it is borderline impossible. Gmail's algorithms end up requiring SMS authentication when you're working over tor, which essentially deanonymizes you or requires the additional step of getting a burner phone for SMS; neither of which is good and probably will get you on all sorts of lists...
The barrier on PGP or GPG is EXTREMELY high for a bunch of normal people on various kinds of cell phones. I can see why someone found an app that someone thought was secure and everyone went with it.