The brilliant thing about Oyster was that they have so much first rate material in their "unlimited" model. There are plenty of arguments to be made about how many books you can read a month etc., but those arguments miss the point. Oyster opened a whole new browsing mindset where you could see a book cover, open it immediately and essentially flip through the book reading bits here and there and re-visit it later if it piqued your interest enough. It's unlike the library where, even in digital libraries, there are queues and "holds" and checkout limits. It's unlike Kindle where you have to commit by actually buying every book which becomes prohibitively expensive if you're just browsing, or Kindle Unlimited where the selection is, as I previously mentioned, dismal. It's hard to imagine until you've used it, but having been an Oyster subscriber for a couple years, I can say it's a shift in the way I think about books.