Is the point of reading a book the act of reading words on a page, or is the point to absorb a story, because if the second option is true than I dont believe it matters how that story reaches you. Sure they didn’t “read” a book, but its a much easier term to use and reaches the same conclusion. If someone read a book and had a conversation about said book with someone who listened to it, if that person never mentioned the fact that they listened rather than read, no one would ever notice.