Mobile developers build huge mac mini rack farms because they need to virtualize osx on top of Apple hardware for CI/CD/testing/store releases (or they used to back when I last worked in mobile dev). That's the bulk of where I've seen MacOS used to control and provision minis (usually with plenty of ansible/chef/etc as well).
10+ devs running integration tests/etc that require different xcode targets, branches, etc. I haven't done this in years but it was a pretty basic mac mini farm 8+ years ago when I did do it with macos + ansible. I really doubt it's changed much (albeit 3rd parties like testflight/etc might be better integrated nowadays). It's a huge reason Macstadium, etc exists where you can just rent mini farms.
