Can you set ACLs on individual fields in a text file?
You can't do that in the registry either. The finest grain thing you can set a permission on is a key. A text file in the user's home directory is the key. That has permissions and ACLs.
Or easily audit changes only to specific settings by specific users?
Only the current user should be able to change a setting in HKCU anyway. Are you saying it's good thing that any user can change stuff in another user's HKU or HKLM instead of an administrator?
Registry ACLs came along later to try and bring some degree of control to the registry free-for-all.
Or find a setting without having to parse the file?
You use a library dedicated to the task. In the Windows world I assume it's much better because you can use a magic unicorn to parse the registry?
That's a Windows 3.11 level legacy solution and Windows moved away from that type of rubbish text file solution for most OS configs a long time ago...
The registry was in Windows 3.
Of all the things you could choose to like about Windows, you chose the registry. It's monolithic, corruptible, binary, is not removed when the app is removed, and even MS would rather you used %APPDATA%. Now excuse me, there's a popup advert vying for my attention saying I need to run a registry cleaner.