One hell of a feature has been added to Hey:
Now you can send email from your @hey.com address plus external email addresses, domains hosted elsewhere, work accounts on other systems, etc.
While this won’t entice me to make the switch, since I’m pretty happy with my email solution now. But had this option been available before my experiment, I might have given Hey a try.
I still think they should add proper custom domain support. Then I might be tempted to give Hey a try. Mainly because I could then keep my email address the same, and it should be relatively pain free (except the migration of actual emails if needed).