Depending on what this chip really does, it may allow Apple to support Blu-Ray movie playback without ruining the rest of Mac OS X.
One of the big problems with Windows Vista is that it supports software playback of HD content. Thanks to the requirements imposed by the movie studios, Microsoft has had to specify and develop (whether it works or not) massive amounts of DRM infrastructure, including CODECs that keep the video encrypted during the decoding process, the ability to selectively detect and disable video cards that don't observe the rules, tilt-bits to detect bus-snoopers, etc.
I suspect Apple doesn't want to play this game. If I were them, I'd refuse to compromise a good multimedia architecture simply because some movie studios demand it.
One possible way around all this might be a dedicated HD-decode chip, as a part of the video card. Mac OS can then feed the raw, encrypted, content from the disc straight to the chip, where the video goes straight to the video output, without ever passing through main memory. Sort of like the overlay model used by video-playback cards, back before CPUs were powerful enough to play real-time video.
This way, the studios get their insane encryption requirements met and Mac OS doesn't get crippled by the attempt to enforce it.
And, of course, when you're not playing a BD movie, you've got a nice powerful auxiliary GPU that can be used for whatever else the system needs.
