You're right about the usability difficulties of syncing local keystores across devices and with the server. Fortunately some good work has been done in this a

You're right about the usability difficulties of syncing local keystores across devices and with the server. Fortunately some good work has been done in this area recently: https://autocrypt.org/ https://autocrypt.org/ This stores the private key as a password-encrypted file in a specified location on the IMAP server. It already has multiple interoperable implementations, by the looks of things.