Yes, you can take a book to the park, bed, or bath. But books have many less desirable attributes including their weight and susceptibility to deterioration. Bookshelves may be attractive, but they gobble up space, attract dust, and are, in my office at least, the frequent site of frustrating searches for misplaced titles. Such irritants become major headaches for libraries, bookstores, and publishers. The resulting high inventory and logistics costs mean high prices, outdated material, and limited availability of titles to the consumer.
Books have other limitations.
A term defined in chapter four may not be used again until chapter ten, long after the reader may have forgotten meaning and location. As eyes age, typefaces becomes more difficult to see. Books intended as texts have further limitations. They are typically designed for the less than average student. Linear by design, the student progresses through the book from front to the back and from the top of the page to the bottom.