People run their stuff in docker cause it tends to make the process more straight forward.
The question is specifically about isolating your torrent client to a VPN only network, that way leaks are impossible since if the VPN goes down, there are no other networks accessible to the container.
Doesn't QBittorrent already have its own setting for that? Like you can set the network interface to wg-mullvad or whatever and then it won't work outside of that? Or is the docker thing just for an extra layer of protection on top of that?