Re: Why the fuck
MacOS is a great choice of Apple development.
For anything else? Not so much. It's too different from "normal" unicies for a smooth experience. At that level, you're probably much better off with a customized BSD or Linux distribution. But there is no real one size fits all answer ... you need to customize it for yourself. Only you know your own needs.
"but should he really care if everything "just works"."
That devolves into "How many angels can dance on the head of a pin" territory. First of all, define "just works". And for whom. And for how long. And for what reason(s). And to what end. Etc.