You do actually need to run it on a Mac, if (and only if!) you require integration with Mac-only software. But the main factor is probably just "all the cool kids are doing it" ;)

iMessage… and safari. Browsing the web from a headless vps has hurdles.

iMessage is the only explanation I can find. Minis aren’t powerful enough for agentic models unless you’re getting a rather expensive version (I could see the MX Pro w/ 64GB working). At which point they don’t have the price appeal of the base model anymore.