I like to read schlocky fantasy novels and mysteries when I'm winding down in the evening, and I can plow through a book in a week easily; two or three days if I don't have a lot to do, and less than that if I have a long flight. If this offers me the ability to snag every book in a series (say, all of Richard Stark's Parker novels, or all of Robert Parker's Spenser novels), then that actually sounds like an incredible deal.

Maybe a lot of people won't get a benefit out of it, but I could easily spend more than ten bucks a month on ebooks that I don't actually care about owning for long periods of time.