One simple answer can be “because we can” – the CPU+FPGA based camera system can simultaneously handle multiple small image sensors we love – sensors perfected by the cellphone industry.
Of course it is also possible to connect one large (high resolution/high FPS) sensor or even to use multiple camera system for one really fast sensor – we did such trick with the NC323 camera for book scanning, but
we believe that the future is with the multiple view systems that combine images from several synchronized cameras using computational photography rather than large lens/large sensor traditional cameras.