They are important as they introduce the audience to the film and gives them a feel for what it is about such as what genre it is and then say if it is a horror it gives a fear factor or a comedy would have a comical start. By seeing this in the opening scene it grasps your attention and makes you want to find out what is going to happen so you keep watching. Without them we wouldn't have a good idea about what is going on in the film, some opening title sequences can tell the story line through edits and animations. Without them the viewers wouldn't know who was in it, this is important as people like to know who is playing which character.