Yes. The movie 'Monster' is indeed based on a true story. It delves into the life of Aileen Wuornos. She had a very difficult and tragic past which led her to commit multiple murders. The film tries to show the different aspects of her life, from her troubled upbringing to her encounters with her victims. It gives an in - depth look at what might have driven her to such heinous crimes.
The connection to reality. Knowing that there is some basis in truth makes it more exciting. For example, if a movie is about a real - life prehistoric monster - like creature, it gives the audience a sense of wonder about what really might have happened in the past.