Tell us about yourself!
Like was already said an FPGA would murder a pi cluster on both watts per mip and cost. Heck even a quad i5 would murder them on the same accounts.
In that use case for sure it makes all the sense. Low power usage / lots of io and can run a gp os.
I know and not arguing that but in that case watt per mips would still make the pi unusable. It would literally take you 10 years to make 1 coin using a pi zero. FPGA are very good at set parallel tasks and even beat out top end intels using a fraction of the power. The pi's arm cpu has a very weak fpu and gpu so it's just not well suited to the task at all.