Because it was part of the marketing campaign to get people to see it in the theatres. It was an experience that you were unable to get in any other way, and s

Because it was part of the marketing campaign to get people to see it in the theatres. It was an experience that you were unable to get in any other way, and so it was more special and (theoretically) should draw more people to it. I went to it, and all the little touches (like the pamphlets) were really well done, and it was indeed a special, memorable experience. It's like limited-edition figures or tins. Some people buy them because they're limited, and it's part of the selling point. The company can't later release it because it'd no longer fit the original sales spiel.