Might I suggest you go to your Apple TV and select Movies and Search. Enter Elvis Presley, for example. Select "Elvis Presley" on the right side under Actors and Directors. Since you are in Movies, one would expect all movies that Elvis Presley starred in to appear. No, we see all Elvis Presley Music for sale. If one was searching for Elvis Presley Music, they would normally go to Music and Search.
To test, enter any Music Artist that has also starred in films to see what results Apple TV returns. While your at it, enter Goldie Hawn. Apple TV will return: "Item Not Available, The item you've requested is not available in the iTunes U.S. store." If you run iTunes on your computer and search for Goldie Hawn, you will find several movies that Goldie Hawn has appeared in. I've noticed several movies that do not show all of the actors/actresses that appeared in the film. The data on the back end has to be correct for Siri to work properly. If not, why bother.