i think it did say that it would be backward compatible with copper wired USB i.e. USB 1.1 and 2.0
and i dont think that in the time it would take to change the signals from the Northbridge and CPU from a digital signal to a beam of light then change the beam of light back into a digital signal and process it would be that much faster, if anything it would be slower, than just a copper strip in the motherboard
then again if you had multiple CPU is a huge server rack and had the motherboard further away it might work...lol