The nice thing about FPGAs is that they are in-between of running a program on a general PC and designing an ASIC. You can test specific implementations that are much faster than a CPU, less expensive than an ASIC, and depending on the application, can be necessary. For example, many radar signal processing research groups tend to use FPGAs, because the size is small enough for most applications, it is cheaper and has a much faster turn around than an ASIC. It can run at much higher frequencies than running Python on a computer, and will also achieve desired throughput.

FPGAs are also a good investment because they are reprogrammable hence reusable. One can purchase an FPGA from xilinx for $800 while an ASIC can cost in the upward range of $300000.