Since there's some feature such as auto-hide item in the toolbar, the highlight border, the MacOS button ( I assume there is), ... and some more that the user want to disable them, so it's better to make it's easy as an option true/false in about:config
Since there's some feature such as auto-hide item in the toolbar, the highlight border, the MacOS button ( I assume there is), ... and some more that the user want to disable them, so it's better to make it's easy as an option true/false in about:config