Object access auditing has been around in NT since the mid-1990s, if not from the beginning. It's not some secret spyware, it is literally a feature that is widely used and is a requirement for high-security environments (e.g. government systems) when you need to be able to log or prove if someone did or did not access some sensitive information. E.g. insider threat scenario.

https://docs.microsoft.com/en-us/windows/security/threat-pro...