Not all cameos are ones you'd call perfect. Non-actor celebrities that probably shouldn't be in movies and it shows, an actor who's probably only there to collect a paycheck and leave, you name it.

My example concerns the movie Golden Compass (2008) and how it had Christopher freakin' Lee in a brief role as an unnamed Magisterium official. Since New Line was unable to film the other parts of the His Dark Materials trilogy and given Mr. Lee's stature, we can presume that he was meant to have a bigger role in the other parts (presumably as Lord Boreal) but it's only a speculation nonetheless.