I think this is the biggest problem with cryptocurrencies. Reversible and traceable transactions are a feature of real money, not a bug.
That depends. Having a paper trail of your money in local tax office sometimes means you would be shot in a head and buried in a nearest forest.
When armed insurgency happens (and yes, they do happen) all you see in the news is "Country A" occupied parts of "Country B", but on the ground you would have armed people going full-DAESH on local tax offices to see whom to demand ransom from and that would be law-obeying people with paper trail for their earnings.
Looking at the big picture, this is even worse: the way you don’t have Daesh is by having a strong society which has the resources to fight them off. A society with rampant corruption and black market activity is exactly how you create the conditions for them to thrive!