In my case I had two systems with 10x 2080tis in them that were being used for ML stuff. But the memory limits were annoying, and when ethereum mining really hit high swing I was able to sell the cards for a great price (even though 3xxx cards were out). I expected to replace them with faster modern cards with more memory at the same price later but we really haven't gotten there yet-- gpu prices are still super inflated and all except the most absurd cards are still memory starved (for ML). In the interim it turned out to be really cheap to get K80s.