This feature is to simply allow the option to change the location of the vertical tab bar. This will not affect the philosophy of Apple's Safari UI design for making the most out of vertical space for navigation/viewing. We will only be shifting the current occupied tab space to the right as a user option.
This will make it easier for users who are working on laptops who are used to reading the website viewing space on the left handside of the screen. It also will make it easier for users who work with multi-monitor setups who prefer their viewing space to be on the left on their screenspace. If a user is centered between a multi-monitor setup it might be beneficial to "center" the viewing space as much as possible to the user. This option provides such liberty.
This will assist users who come from different browsers who may have had the panel shifted to the right (myself coming from Vivaldi). It will also promote more freedom in user choice to customize the browser regarding vertical tabs.
Vivaldi accomplishes this as so in their Settings:
My suggestion to tuck the " Swap Location " in the nested windows options menu is merely a suggestion but makes it appropriate for a one-time / not-often used tool to swap its location. It is designed to be minimal and not hog as much space as Vivaldi does on UX.
