"Isn't this just LapLink with a Thunderbolt cable" was my immediate thought when I read this. If you're around long enough everything is shiny and new, even the things that you thought were long ago killed by better solutions (like Ethernet in this case).
For general networking, sure Ethernet is a better solution, but I also don't imagine you're going to get 18Gbit/s+ from regular desktop/laptops over ethernet, regardless of how much gold plating it has.