4 words that explain why, if I ever wanted to collect movies, they would all be DRM-free torrents.
When the "legal" way to do it is self-evidently a scam perpetuated by corporations and governments working together against our interests, then they only honourable ways are either to watch illegal downloads or not watch movies at all.
Why eschew ripping physical media? You'll likely have a more uniform collection in terms of quality. Also depending where you are in the world, it's either legal or just as legal as torrenting media. In the latter case, it's not really enforced. It's also probably more honourable, if that's something you really care about.
You need a real computer to rip BDs. A netbook or a Raspberry Pi aren't going to cut it because of the CPU requirements. Said Pi will have no trouble running a torrent client though.
:)