That is for applications that need access to a LOCAL_SERVICE while not in foreground. That’s like Geolocation or screen orientation. VPN is not one of those. You can kill the foreground application from the recent apps by sliding up.

No real VPN app needs to have an application window and a background service (same thread) running to provide a VPN. If it does, it is doing something else not related to VPN.

If you want to add a pause button, applications can add custom tiles.