It's probably more than powerful enough to emulate a C64... where the computer is literally inside the keyboard.
But with all the concern over malicious USB devices, I'll take a dumb and simple PS/2 keyboard with a mask-programmed 8048 over anything "smarter". Otherwise, his idea of requiring a special key combination to enter firmware update mode is also good - something like "unplug, then hold down X while plugging in" easily stops any malware attempting to do a silent firmware update.