Re: It's nice to see someone normal for a change
Actually (and I can't believe I'm actually saying this) but there are reasons or scenarios for installing a mail server on Windows, especially for home users.
Firstly, in some instances, the installation and running/maintenance of the software can be a bit easier, depending on your chosen package (Postfix - why? There are easier, free options out there). Or, at worst, it can be a little less scary and a little more more manageable if something goes wrong (if you're not too familiar with Linux for example).
Secondly, mail servers take up surprisingly little resources. For one person or a family, it's basically sod all. If someone has a half-decent desktop PC that's 'on' all the time then running their mail server on that in the background would cost precisely £0 extra in hardware outlay. With the right software and restricting port access to just those needed (and also from *where* needed, i.e. your MXs), and *not* *ever* *under* *no* *circumstances* having your home server as your domain MX, all but the most paranoid should be good to go.
A loooong time ago I used to run CommuniGate Pro on a Windows server — which, to add to the list, is free for up to five users so ideal for home experimentation (just a happy user) — and it was basically an indestructible tank... it would have run unaided for decades if I'd let it!
(OK, to be fair, these days I run server stuff mostly on Linux on virtual and cloud platforms, because I can, so I do... ;-)