Many people have problems with reading or don't like to read books. Those people might prefer to see a movie in order to avoid reading.
Some people, especially impatient ones, might want to know about a certain story fast. Because the movie usually takes 2-3 before it is completed, it is considered the faster way.
Many people aren't aware of the fact that some books can be very different from movies when it comes to details or even the story itself.
Some people might want to watch a certain story with friends. In such a case, the movie represents the best option for them.
People who can hardly imagine events in their brains might have problems reading about a certain story. Those people find it much easier to watch a movie as the visualization work is done for them. See also why some people like Horror movies.
The movie experience will usually be more indulging. The sounds effects, the music, the visuals and the other effects combined make the experience more real to many people.
Many people prefer to watch movies and don't like to read the books because they don't really care about knowing more details as long as they get a chance to see the full story.
According to psychologists, thrill seekers are the type of people who always seek some kind of stimulation to stay excited. Thrill seekers might find books boring compared to movies. See why some people like war movies.
Many people enjoy going to the movies no matter kind of movie they are seeing. It is considered a pleasant event where they meet friends, buy popcorn and enjoy the movie.
Many people go to the movies without realizing that some of them are actually based on books or novels. Those people usually follow the latest news about movies and watch them as soon as they are released.