In an interview with Famitsu Xbox, Microsoft Japan's Xbox operations chief Yoshihiro Maruyama said that Microsoft's planned introduction of HD-DVD to the Xbox 360 console in the future will be for movies.

It's a possibility, but it won't have any relationship to gaming," Maruyama is quoted as saying. "If the Xbox 360 uses a next-generation DVD drive in the future, it will only be used for watching movies that run on next-generation DVDs. The format for games will remain as [standard] DVD. That's not going to change."

GameSpot Speculates

While it seems odd to add on hardware that could benefit game developers and then disallow them from using it, Microsoft might have good reason for it. Introducing an HD-DVD-equipped Xbox 360 would create at least three (and possibly four, if it came with or without the hard-drive add-on) significantly different hardware setups for developers to work with. Microsoft has already indicated that it wants every Xbox 360 game to play on a no-frills core system.