After the attack in 2014 the DPRK found itself off the WWW a couple of times for many hours and blamed the US for this outage.
Since you need to have government permission for Internet access most people don't, only a very small percentage of their population do.
So if the general public can't find out what's going on in the world I say shut them down if it's no use to the masses what use is it but to allow gov, sanctioned attacks and misinformation to be spread, you'll still have to deal with sympathetic offshore groups hacking of course.
Pull the plug along with the rest of the sanctions!