Before I start - by "what is a book worth in the 21st century ?" do you mean non-fiction? Because then we agree on that point. However... There is no such thin

Before I start - by "what is a book worth in the 21st century ?" do you mean non-fiction? Because then we agree on that point. However... There is no such thing as "intellectual superiority". All life (I will grudgingly accept limiting it to humans for this discussion) has equal value regardless of perceived intellect. I may be good at growing plants, you may be good at researching nuclear fusion. This does not make either intellectually superior (ego and god complexes notwithstanding). Second, books in bookshelves have value beyond the $ value or content of the books in them. At minimum it's an interior design tool that brings life and warmth to an otherwise soul- and lifeless house (look at houses on YT with a value > $10m. - virtuall all of them clinically and lifelessly designed by "x" who is "amazing darling"). Books do what a drawing of your child does when framed and hung on a wall - they make a house look lived in. The people in it automatically gain depth that a framed photo by some famous photographer of a landscape or half-naked person can never deliver. Books can give insight not found on the Internet. King Rat, by James Clavell (himself a former prisoner of Changi) gives insights that are rare as hens' teeth on the Internet, if they exist there at all. Another stand-out is The Ugly American which surfaces some uncomfortable truths that can alter lives. And they start conversations, excercising intellects. Finally, worth. A book in the 21st century is worth at least as much as a movie. I say at least because it has secondary benefits like improving grammar, spelling and sometimes writing style. I don't believe a Twitter feed or blog can match a good book for unadulterated storytelling.