The intro movie is usually the longest cut-scene of the entire game, telling you who made the game, setting up the story,etc. The first time the gamer sees this intro, he usually doesn't mind. But certain games encourage multiple playthroughs and having to sit through the same 10 minute intro again and again when all the player wants is to play can become frustrating.
This concept must not be mistaken with cut scenes that hide loading times since once the loading is finished they give you the option to skip said cut-scene. Here you are condemned to watch the same intro movie every time you want to start a new game.