>pretty successfully with email

Indeed. I was going to register an account somewhere the other day, and the signup form had a list of acceptable email domains. Gmail, Protonmail, Outlook, Yahoo, Icloud... a few others. It's not the first time that's happened to me. Sad.

EDIT: Didn't even include Fastmail, who's pretty big after all. They host MX for my domain, so I could have "circumvented" it that way with their disposable address feature, but nope.