If you look at the different iterations of the xbox 360, the final model, Model E had only audio via the Hdmi port. The most popular console is the Model S it seems, it was easily modded and had optical out for audio. If you could, optical would appeal to a lot of people. Although the model E had the Winchester motherboard which can't be modded, a lot of people like the optical option of the model S. If you watch the MetalJesus review of the 360, they talk about this very point. Thought worth sharing.