As a medium Budget Gamer I totally agree, 5k for an apple imac pro is overpriced. I think you made the right decision. Its mostly designed for graphic designer but If you look closer than you do not get what you deserve.
With the nvida 1080, you should be able to get stable 60 frames on ultra even in 4k in almost all AAA-games. For Crypto Trading even a 5 year old PC will be good enough.
World of Tanks Rocks!