Another big advantage of FPGAs is low latency and the ability to hit precise timing deadlines. When working with radio hardware, you still need an FPGA for automatic gain control calculations and recording/playing out samples. Similarly, you need to do your CRC and other calculations in an FPGA if you need to immediately respond to incoming signals, such as the CTS->RTS->DATA->ACK exchange in 802.11.
I think that's the big advantage of FPGA. If you need acceleration to hit a 10 microsecond latency target, FPGA is what you need. If your latency target is like a millisecond or longer, then GPU can handle a lot more throughput. But GPU can't typically give you a 10-us guarantee.
Okay, bit-banging is another advantage of FPGA that GPU doesn't do as well. There are a few things.
Regarding DNN inference FPGA can provide low latency AND higher throughput than GPUS.
If you want to compare apples-to-apples, we have done a comparison with realistic (and not synthetic) data regarding the performance of GPUs and FPGAs.
