What I pieced together from the referenced “dark forest” article, ethereum cryptocurrency allows you to upload programs (smart contracts) that specify under what conditions cryptocurrency changes hands. If there are bugs in these programs, the money can be stolen. Fixing the bugs after the fact is only possible with new contracts, and there are bad actors constantly scanning the newly uploaded contracts, copy them while making themselves the beneficiary. This is fully automated. To bypass this they gave the contract directly to a miner, so it is only publicly visible after it is run/completed. I can imagine the appeal of working on this, it is really a specialized type of unpaid white hat security researcher.