Following latest round of sanctions even their biggest banks are now not able to transact internationally. North Korea is the only truly independent county. It is also independent from international banking oligopoly. They have nothing to lose. Introducing bitcoin as a settlement unit in their international economic relations is an exceptional opportunity for this country!
north korea has full control of its currency. no manipulation by wall street. no IMF, no outside influence.
however. using bitcoin although still avoiding the 'elitist' manipulation of the fiat puppeteers. it then becomes reactive to natural economics of international barter. which is the other end of the scale, and can reduce their control based on being too open.
i dont think they will want to be controlled by the wall street elite.. or lose control by the open market. they will want to remain right in the middle of self control of their own currency.
that said the citizens will always find a way to barter with bitcoin, even if it involves under the table private blackmarket trading beyond korean government oversight