As far as i can see, the extension is just a user interface (front end?) to operate the ordinary utorrent application from within your browser. You still need the app to be installed. It will then not use opera vpn.
I found this torrent website, accessible from any browser, no extension, but i didn't manage to get beyond 0% dl progress yet. It is suppose to work both with opera vpn and in tor, the ladder strictly prohibiting the use and possibly blocking it though.