My biggest hesitation here is that you're still trusting the server. Which, not coincidentally, has always been one of the biggest objections to JS crypto. That is, if the server is compromised, it can serve malicious JS, and it can just as easily steal any data that's being encrypted server-side.
To me, one of the most important things about PGP is that the plaintext and the encryption process are entirely in your control. (At least to the extent that you control your own computer.) You lose that assurance if you do server-side encryption.
To me, one of the most important things about PGP is that the plaintext and the encryption process are entirely in your control. (At least to the extent that you control your own computer.) You lose that assurance if you do server-side encryption.