Comment by domlaut

It's a reasonable policy for Apple-owned Apple IDs on their public domains (@icloud.com, @mac.com, @me.com), but I don't see how it makes sense for privately owned domains you're already in control of the DNS for. You could use any other mail provider or routing service and get access to any emails that way -- then do a password for any other service where the address used was on the domain you were in control of.