Well, maybe, though an external DVD drive probably costs no more than three or four movies, and then you can make yourself non-DRM digital copies too. (As long as you don't need BluRay and HD).
I place a big value on not owning things I don't want, like external DVD drives. I'd pay more for a virtual one-time-viewing copy than I would for a DVD even if it came with a DVD drive. I specifically want to not own one.