If these USB displays provide as high a viewing experience as HDMI cable displays and supply the display power as well it may be that USB will eventually displace HDMI due to the higher production volumes and consequently lower costs for USB cables.
In the USB IF exhibit area at the CES I saw a high definition display that only had a USB cable connected to it that provided power for the display as well as a channel for the video traffic.
Silicon photonics is a new approach to using light (photons) to move huge amounts of data at very high speeds with extremely low power over a thin optical fiber rather than using electrical signals over a copper cable.