If you were putting our computing resources head-to-head (my Pi vs his Spartan FPGA), sure. But you have to consider that the LED strips in both of our systems are the most power-hungry part, potentially drawing up to 1A per meter.
Taking that into account, the difference in power drain for our respective computing resources would be dwarfed by the power requirements for the LEDs, such that the difference is near negligable.
Cheaper? Definitely not
Lower latency? Likely, but the difference in latency would be undetectable
Way Cooler? Yeah, I'll give him that one.