Then you didn’t use it correctly. It absolutely works, and is a long-time feature of macOS. Maybe you just are not noticing its effect. Nothing dramatic happens. But when you are in a Finder window and toggle on hidden files, they appear in grey text with somewhat faded icons. If there are no hidden files in the folder you are viewing, you will not see any change. For complete explanation and illustration, go to macOS Help and search for “hidden files.”