If I verified the domain, why do I have to also confirm each email address? I want to be able to send from a@mydomain and b@mydomain and c@mydomain without having to confirm each.
I don't believe it'd hurt the Sending Service or its deliverability if replies bounce. Plus, the verification of an email address is a one-time thing, not helping ongoing deliverability concerns, such as if b@mydomain account gets closed.
If anything, let's implement Return-Path (https://sendgrid.com/blog/what-is-return-path/) and not need to confirm every single email but only the email that is added to my account's bounce / Return-Path settings.