Lenses which cover 8*8 are basically large format lenses which include leaf shutters. Leaf shutters have a couple of problems - limited size, and a limited upper speed. Typically 1/500th is the fastest a leaf shutter will operate, and the limited diameter means you typically are down to f5.6 or f8 as a maximum aperture.
The maximum aperture will limit the speed advantage against a 35mm DSLR or medium format where f/2 and faster is common (f/1 can be achived at standard lengths if you compromise on image quality, say a noctilux). f/1 vs f/5.6 is 5 stops, or 32 times the amount of light. So an f/1 lens vs an f/5.6 will accept 32 times as much light to start with
The usual complaint about fast lenses is the limited depth of field. However, large format at f/5.6 will also suffer this problem as the larger image format will also offer a limited DOF, but in addition, a slow lens. I guess the answer will be to run the sensor at a higher ISO equivalent, make it more sensitive, and hence allow a smaller aperture to be used, but the tradeoff isn't obvious from the specifications
My guess is that this is a technology demonstrator, and will not be available to average punters on real cameras. Saying that an old large format camera with a 8*8 back would be very cool