Why would you trust an online service if it's super easy to generate a keypair, pass around your public key and receive messages only you can decrypt afterwards...
It's not that easy, it takes a while to figure it out. If it would be super easy, everyone would be using it by now instead of sending unencrypted emails.
It's not that difficult, but it's not convenient since you need to perform encrypt and decrypt manually.
It would be really cool if some sort of client-side encryption can be added by default to PMs though. Maybe in Epochtalk?
Interesting idea, maybe we can add PGP database as well where user can upload their public PGP key.