It's pretty clear that the N Korean shenanigans are purely for domestic consumptiion, a way to distract their own power structure from the disastrous results of their own mismanagement and the unfortunate consequences of their own ideology.

Unfortunately, this sort of policy can easily get out of control. Events are set in motion which tend to take on a life of their own, particularly when they are directed at an opposition (or an ally!) that may interpret or respond to them in unpredictable ways. This is how World War I got started (to choose an example from safely in the past...)

As Caspar Gutman put it: