Guess what’s inside a lot of mining rigs? Gowan, guess.
Graphics cards!
Lots and lots of these puppies side by side, spinning their little fans as fast as they can go because as it turns out: GPUs are perfect for doing the calculations required for mining cryptocurrency.
Which means amateur miners buy a lot of these things.
So many, in fact, that there is now (May 2021) a world-wide shortage of NVIDIA and AMD graphics cards and building a new gaming rig is damn near impossible because of the shortage.
OR you can pay a ridiculously inflated price by GPU scalpers on eBay.
Seriously. Places that sell GPUs impose quantity limits because if they don’t… some crypto asshole will buy out their entire stock in one go.
But the “good” news is that the professional miners (like the Bitmain site up there, in the photos) use dedicated ASIC mining rigs which don’t use consumer GPUs. But (bad news) they DO use the same sort of chips that NVIDIA & AMD rely on to make their products, which just starves the supply pipeline at a different point.
Bottom line: not only does cryptocurrency mining consume terawatts of electricity, it also consumes megatons of computer hardware. Which is expensive to produce (in resource terms, like rare metals, petroleum, water, electricity, paper) and will, someday, require even MORE resources to recycle. Or else it ends up in a landfill.
Note that current dedicated mining rigs are so highly specialized they are useless for anything other than mining. They cannot be easily repurposed to (say) sequence DNA or fold proteins for miracle cures.