I think it depends, but they can be a great gift. I've only ever given the movie gift cards myself, and I've only done that twice.
One year I gave a movie gift card to a friend who's life wasn't going very well. She had two small children, was very tight for cash and living with her ex-inlaws (It's a long story). It didn't cost me much money, but if I had just given her 20 dollars or so, she just would have spent it on diapers or what ever. This way I was able to give her an much deserved evening out, and she really appreciated it! She told me it was the best gift she got.