Well, I block all connections to iCloud for every app (user and system) completely with Little Snitch, and the fact that it does indeed break some little featur

Well, I block all connections to iCloud for every app (user and system) completely with Little Snitch, and the fact that it does indeed break some little features I can absolutely live without, indicates that it has at least some effect. But still, I fully share the sentiment that creators of an OS are perfectly capable of bypassing whatever there is running on top of it.