Watching TV isn't the same as reading a book though - at least in terms of its effect on your brain. People aren't reading books because a film or tv series is more exciting - it's more stimulation.
We aren't going to all have nervous breakdowns because we watched game of thrones instead of reading the book but the brain is releasing chemicals based on this stimulation.
What effect that has I don't know - we weren't designed to be responding to stimulation every waking moment though.