For me for example its “Eat me - a natural and unnatural history of cannibalism” by Bill Schutt. Its an amazing book that covers cannibalism in animals and then the history of it in humans (cultural, survival & medicinal cannibalism).
I got a lot of “oh why would someone read something like that?” And “that not something fun to read about!” From relatives but my friends enjoyed the stuff that I could tell them about cannibalism!
Libraries only have a certain number of “copies” of digital books that they are authorized lend out at any one time. Yes, it’s a little ridiculous, but if it was unlimited, the idea is no one would ever buy an e-book.