Why? The best actors are very often writers. Writing costs nothing. Way too many actors to remain passive and wait for someone to cast you in a role, and someone else to tell you what to say and where to stand. If you want to be part of the film industry, learn how to make films. Nobody knew it all before starting, and just working as an actor will require that you learn the process. You'll need to know the basics, like how light shines on your face, the difference between different techniques, how to direct your performance based on a specific shot or angle, and how to edit for the many times you'll be stuck shooting out of context inserts to be pieced together in post.