+1 I assumed (more fool me) this would be standard functionality as part of the integration.
The advertising https://1password.com/fastmail/ for this feature is pretty sneaky.
- "Create a new masked email address without ever leaving the sign-up page. Now, keeping your email anonymous is as easy as generating a strong password. Italics is not true.
- "Separate all your online identities and manage it all from a single account." - except existing ones.
- "the same way you’d get a new, random password right when you’re signing up."
It should be clear that this does not work in anyway for existing accounts, making it a lot less valuable for anyone who has existing accounts... which is everyone. Albeit you can trial it.