Adoption increased in Iran with their sanctions.
Russia would have been buying since 2016 if there were any truth to this though.
You realize the difference between people buying coins and a country buying coins?
If Amazon is going to accept bitcoins it won't mean the US is using bitcoins just like one county accepting bitcoin for tax payments in the US doesn't mean every company there deals with coins.
Plus I think people see sanctions as there are some guys monitoring transactions between companies and denying them...
Sanctions don't work like that.
Nobody is going to be able to stop a company in China from buying arms or selling oil to a company in North Korea, everyone could make those deals with bitcoins, with rubles, with yuans or with sheepskins, the problem is what comes after.
For a company that has a single purpose and that is trafficking it matters not, for a multinational one dealing with countries/companies/persons under sanctions means you must prepare for fines in the EU or the US and to say goodbye to a lot more than the profits you have made. Standard Chartered is going to pay another 1.5 billions for getting caught on top of the 800 million paid earlier. This is how sanctions work.
And bitcoin is not going to help you with this one.