If you are using proton for additional "privacy" don't do that, since it would effectively mean that your adversary can now know your new email identity.

If you don't worry about that, then in all honesty it's somewhat redundant.

I use hushmail because it has PGP integrated into their service, including a PGP client in the webmail, yes they have a copy of my key (you can do PGP over JAVA if you want to keep the key on your computer) and yes since they are HIPAA compliant and a Canadian company they will comply with NSL but those aren't threat models i worry about.

I want to be able to use PGP easily and from anyplace and not worrying about having to carry my key with me, having PGP or GPG installed and fussing around with it if I have to access my mail in an emergency from a device that might not have a full setup.

Whilst I am aware that the NSA and other agencies with similar capabilities are technically adversaries I don't fuss about them, I'm more worried about sending my mail to the wrong person than the NSA reading my mails, if they want to they'll be able too regardless of where I host them, and I would never go toe to toe with some one who's likely to use rubber hose cryptography on me.

Hopefully this will be coming soon!