If you stood me in a costume next to a computer graphic of the same-looking character, I think there would be a difference. And many movie fans I've spoken to would rather see an actor in a costume than CG.
“I'd rather see you drink a glass of wine than a glass of milk. So many people drink Coca-Cola and all these soft drinks with sugar. Some of these drinks have 8 or 9 teaspoons of sugar in them What's the good of living if you can't have the things that give a little enjoyment?”