A book can't be spoiled by lousy casting, acting, or directing. Admittedly, they can still suffer from lousy writing or editing.
A book accommodates itself to your schedule.
25% of the length of a book isn't advertising.
There aren't any arguments about what book to read. If three people want to read three different books in the family room at the same time, what's the problem?
Books can be rented for nothing (got a library card?), have a rental period two to three times - or more - as long as for a video, and much smaller penalties for late returns.
A book's batteries don't go dead at inconvenient times. Mostly because books don't NEED batteries.
An ongoing series of books doesn't have to fit its stories into multiples of twenty-three minutes.
Books don't require a high-tech information infrastructure to produce or read, and almost everyone has the equipment necessary to make one to his or her own taste. Skill and motivation might well be a different story, but...