Any attack on North Korea will involve sophisticated electronic attacks on their instruments of war, rather than attacks on their people. Here's Mattis:
https://amp.businessinsider.com/mattis-secret-military-options-for-north-korea-2017-9
The communications systems will be hacked, and artillery pieces will be told to fire at the wrong targets. Units will be made to fire on each other. And most of their guns will be rendered unable to fire.
So we won't see the destruction of North Korea. Only of their offensive military capabilities.