Even if this were simply about obtaining funds, North Korea has slowly tested and pushed back our and South Korea's threshold against limits on conventional attacks time and again. We went from, "If you cross this line, we'll **** you up." to "If you blow up our ships, we'll **** you up" to "If you keep detonating nukes, we'll **** you up....maybe". And every single time, nothing was done to them. Yeah, yeah. Sanctions and trade embargoes en mass, but that hasn't done anything to stall North Korean aggression. What separates the times North Korea shot missiles into the sea and no man's land, which were purely for show, and now is a military installation was actually bombarded this time. And to happen only days after we reveal North Korea has multiple uranium enrichment facilities? That's pretty ballsy. These guys are chess players. They're not planning for a confrontation today or tomorrow. They're in this for the long haul, and their greatest asset is the belief that they're relatively harmless.
Like I said, nothing will come of this, but it's helping to reinforce North Korean beliefs. What belief? That South Korea is too scared to retaliate in a meaningful way. I don't know that that hypothesis isn't unwarranted, either, as SK has more to lose than NK, as all of their batteries are aimed right at Seoul and other population centers. At some point, a real line has to be drawn.
And that's why we need a robot army.