While that is true, that was an application-level implementation. With an OS-level file-system implementation, I could in any application just double-click a Z

While that is true, that was an application-level implementation. With an OS-level file-system implementation, I could in any application just double-click a ZIP file, open a GIF or JPG inside it, make my changes and save back and the ZIP was now updated. It was one of those small things which made a huge difference in the user-experience.