Ask HN: Creative uses for a macOS server?

I have an unused mac that I want to put to work and I'm looking for inspiration. So far the only examples I've found are the typical home server stuff:

- plex/media server

- remote backup

- file sharing/sync

But I'm more interested in scriptable use cases that can't be covered by a Linux server, e.g.:

- Xcode builds

- headless browser service (puppeteer) for website screenshots (for apple emoji & font rendering)

- automated screenshots/screencasts (via screencapture & apple script)

- iCloud file organization (e.g. with Hazel.app)

I'm sure there are many more possibilities, so... if you have a macOS server, what do you use it for?