Ok, compatible within the newer nintendo universe. But not compatible with regular usb nes controllers, probably for the only reason is to make you pay for the nintendo variety instead of utilizing the already supplied market of cheap usb nes controllers.
It's not even compatible with the old nes controllers. At least with a pi, you could rewrire a nes controller to the GPIO or SPI.
Speak for yourself... I'd love to see controllers with the build quality from the SNES and Sega Saturn with a true USB interface. By that I mean, most of the aftermarket controllers suck, and the USB adapters are less than ideal.
It's not even compatible with the old nes controllers. At least with a pi, you could rewrire a nes controller to the GPIO or SPI.