Here is a typical use case :
- our Discourse is private
- diverse partners are sending emails to our generic address like contact@example.com which redirects to the forum. For example: “hey, we inform you that our group organize a wonderful event. The members of your community are welcome!”
(Practically, the email arrive first in a private category, then moderators changes it to a public one when it is relevant.) - then the message is visible to our logged members, and we have internal discussion such as : “I am interested, who want to go with me? I have 3 seats in my car.”
When a reply has to be sent to the partner, we use our official email address to not confuse them. No need to send a reply from Discourse.