but if they were to not be included with a digital purchase/rental then they'd never be watched
True. I could see these becoming a marketing sweetener (well, they already are, but in a different way). Netflix offering one lot of extras, Vudu another, etc, each trying to convince people to sign up with them. Either that, or "Sign up for our $4.99/month Film Buff Club and you'll get loads of extra features for all your rentals, plus some other crap that you'll never actually use!"