Fair. Don't disagree with anything you're saying here.

I should probably tighten up that line. What I really meant to say is that the average self-hoster who just wants to enable a few services to send email doesn't want to run a mail server. Different audiences, different (and both correct) answers.

I set out to solve some pretty specific problems of my own but I'm genuinely curious how others have tackled these things. Posthorn and Postal don't compete in my head. Postal makes you into your own provider, which is something I personally deeply want to avoid. Posthorn assumes you've already picked a provider (which might be Postal, actually, it would work just fine pointed at a self-hosted Postal instance).