Oh, or it could depreciate an entire class of software you may-or-may-not use without any opportunity for replacement besides downgrading your Mac? https://support.apple.com/en-us/103076
More mundane, but it also unconditionally blasts a bunch of config files under /etc that rightfully belong to the user/administrator. I've not seen any OS as willing to simultaneously Sherlock existing apps and rip out the APIs they depend on, either.
macOS upgrades are indeed generally exceptionally disruptive to applications.
macOS upgrades are indeed generally exceptionally disruptive to applications.