Regarding privacy, PGP is far better than out-of-the-shelf IM-embedded encryption, if used correctly. Alice uses Bob's public key to send him a message, and he uses his private key to read it. He uses Alice's public key to send her a message, and she uses her private key to read it. No one can eavesdrop, neither governments, nor corporations, nor crackers, no one except for Alice and Bob. I don't get why someone would complain about "usability", for me, it's perfectly usable. Commercially available "E2EEs" (even Telegram's) aren't trustworthy, as the company can easily embed a third-party public key (owned by themselves) so they can read the supposedly "end-to-end encrypted" messages, like a "master key" for anyone's mailboxes, just like PGP itself has the possibility to encipher the message to multiple recipients (e.g. if Alice needs to send a message to both Bob and Charlie, she uses both Bob's and Charlie's public keys; Bob can use his own private key (he won't need Charlie's private key) to read, while Charlie can use his own private key to do the same).