From my own experience maintaining a mail server for over a decade, I do not agree with this. The time between any tweaks needed is large enough that I complet

From my own experience maintaining a mail server for over a decade, I do not agree with this. The time between any tweaks needed is large enough that I completely forget how it was set up and need to relearn stuff. And it's definitely not trivial, so I can't do that in 5minutes (the way I can with acme/letsencrypt, for example). In the same way that caddy just makes web server setup easy, it's good to have a modern setup supported out of the box for mail as well.