I think you missed the point there somewhere! You wouldn’t just use it to search for lines you already knew were in the book, you could use it to search the book like you’d search the Internet. Say you had a book on Android, you could search it for “Book search” to find out where in the book you could read about how to search books (bit of a self referential argument there, but I couldn’t think of a better example!)

I think that is pretty amazing!