> undocumented immigrants? Countries allow them in to exploit for cheap labor
It seems you've answered your own question.
Your argument seems constructed as a red hering, "what about <this group of people left in legal limbo by the politicians>, wouldn't they benefit from <the speculative financial scheme I have a stake in, that the state can't track or ban>?". The solution to that problem is, you know, to not have people put into a situation where they are exploited and do not have legal rights; and in general, the solution to human rights failures in democracies surely isn't the suspension of laws, it's better laws and better systems put in place to protect those legal rights.
In the great scheme of things, undocumented migrants in 1st world economies are far from the wretched of the earth I was referring to. For example, it has recently emerged that a fellow country man of mine was involved in supplying european mercenaries into the DR Congo, which were caught in the rebel capture of Goma early 2025. The ring leader was found to have laundered a few millions of euros through cryptocurrency he earned from Congo.
DRC is one of the poorest countries on earth, with the majority of its population without electricity, internet, smartphones etc. They are the real "unbanked" and what bitcoin has done for them is to enable war. Now, it's very likely that the war would have been exactly the same if the mercs were paid using the traditional financial system, but at least that would leave traces and discouraged some of the mercs, since it's an illegal profession in many european countries of origin.
I don't have a solution for all the world's troubles, but this dystopia where you can anonymously buy armed soldiers on the internet to prop up your authoritarian regime or guerilla faction, surely isn't the best of all possible worlds.