As soon as the Mullahs get the bomb that's exactly what they'll do... well, 10 seconds after bombing Israel.
That said, North Korea's the armpit of the world. They should be laughed off the face of the earth... Bombing a country that has nothing and is nothing is a waste of time. Get with China and kill all members of the administration. The people there are slaves - there's no purpose to include them in the slaughter.
If you look at the night photos, there is only light in one spot.
It is possible to make the blackness uniform. By destroying the light in the one spot, there can be uniform blackness and then the possibility of light springing up all over.
They have nuclear weapons and are using them to extort money and aid from the US and its allies. Precisely because it has "nothing," is the reason why we should be worried. They will sell and trade their nuclear technology with anyone who has money. They were involved in the nuclear facility that was destroyed by Israel in Syria. They are working closely with the Iranians.
Would NK sell their technology to non-state actors, i.e., terrorist groups? I think we are being very foolish if we believe with can contain the NK nuclear program. And it sends a message to others like Iran, Syria, etc. If you want to ensure that the US stays out of your internal affairs, get a nuclear weapon.