Sure, you just add a toggle switch in a dialog, or make it part of the preferences, or use something like privacy badger to keep that library from even loading. Or detect if the browser is mobile and disable it all together. There are quite a few options.
It works sort of like a cache. If the media isn’t being seeded, then it pulls from the web source (S3 in our case). However, since web torrent can also pull from traditional torrent clients like transmission, rtorrent, etc, we can have a few seeders (like myself) who just seed a whole bunch of stuff on my home connection. You really only need a handful of seeders to make this viable.
Indeed so, but we’d solve that problem as a community.