You're only thinking of the technical angle here. If there were no valid existing answers to your questions, Mailgun, Sendgrid and others would not exist, righ

You're only thinking of the technical angle here. If there were no valid existing answers to your questions, Mailgun, Sendgrid and others would not exist, right? These platforms provide OOB business and productivity tools (logs, metrics, dashboards, API integrations, etc) that Postfix does not. Sure you can write all your own stuff on top of Postfix, but not everyone wants to do that.