I mean, I can meet you in an ally, transfer some satoshis from my wallet to yours, you hand me a wad of cash/jewels/MtG/collector funkos and you might not even know my name.
I'm assuming I'm purchasing/selling a lot of MtG/Funko here in this example.
10M might not be as noticeable but crypto being nominally in a country on its own isn’t that useful as you still want to be able to spend it at the end of the day.
Bisq is one place, there's more.
Crime is risky, but not pure anarchy. It is still based on trust and rules, just not those written in the law.
There are plenty of regular people who interact with criminals, for example drug dealers, without getting murdered or robbed of all the cash they are carrying.
In Argentina, years ago, you could exchange dollars/euros for pesos on the street and get a far better exchange rate than in a bank. It was obviously aimed at tourists, who didn't get robbed, or the whole enterprise would stop.
For big transactions where something of actual value is exchanged, both parties will want an escrow, and this is where a public exchange comes in.
I have heard from friends who are in these countries observing transactions that go into the millions of dollars that are being cashed out (not even laundered) like it's just another day. Nobody asks questions, nobody cares either and if you bring it up you will likely lose your job in few months or so.
Escrow companies open and close all the time for this very reason. People wash money alllll day long with US real estate for this reason.