I can't say much about the macOS market, but I do know that MDM-style APIs are practically the only way to write a third party control app for mobile devices. With the way Apple is moving macOS more and more towards their control, this may happen on the desktop in the future as well.
Schools also tend to use MDMs, but often in combination with Chromebooks which don't typically run third party software anyway.
For certain types of apps from the mac app store vs installed directly (mostly VPNs), they also have to use the MDM APIs and install profiles on the device to function.
So if a home user, for example, uses Tailscale and installed it via the mac app store, they'd flag as being MDM managed if the software used the code in the article.
Fonts on iPad work the same way, the font apps install an MDM profile to install the fonts on the device because Apple gates this behind that for some stupid reason.
Like you said, I suspect doing things through configuration/MDM profiles is going to become more and more common on desktop like it has on mobile.
Schools also tend to use MDMs, but often in combination with Chromebooks which don't typically run third party software anyway.