From the comments after the article:
A big limitation is DRM. If you are using a HDMI switching AV
receiver in your home theater set up, many of the middle-men
devices may be blocked as the cable boxes only allow one
device between themselves and the display.
This is what I've been thinking since the announcement. Wouldn't anybody who takes their tv serious enough to want this already have their stuff running through surround sound? Even if it works, how many boxes do they expect us to pass through?