The value of NK isn't anything internally intrinsic; the main reason it has "survived" with its current and past leadership is that it is a buffer between the "West" and China. And previously it was seen as a buffer between Japan (and also the US) and Russia; Stalin was the one who authorised the Soviet invasion of Manchuria in the very last days of WWII. Russia's leadership at the time remembered Russia loss of face (and territory) to Japan in 1905; remind you of current day invasions and annexations with ruminations of nationalism?

The Korean War was in many ways similar to a "more power" version of Ukraine today.