Books can be a double-edged sword. If you own a book (or a bookshelf), it makes us feel smart. If we're not as well-read, however, we might enter a bookstore and feel quite ignorant because of all the books we haven't read.
Moral of the story? Stare at books you've already read before. You'll feel better.
But honestly, intelligence, and more importantly, maturity isn't about how many books you've read or know about. It's about applying what you've read and experienced.
Perhaps that's the beauty of children's books. There's no need to prove to one's ego that you need to read a thick book to read a good book. More isn't necessarily better. And sometimes, the message is clearer, simpler, and more concise. Wisdom isn't exclusive to complexity after all.
There's beauty in long, complicated narratives too. It challenges our self, our discipline, our perception, our cognitive processes, and our soul. It won't always be easy, but medicine didn't always come in sweet packages.