Keep something important in mind, military is not about aesthetics but practicality ,utility, survivability etc. North Korea has a very weak economy with a GDP of only $28B, they would never be able to match Iranian production of missiles. Whenever anyone poses the question you have, I ask them the same type of question. Suppose you had 2 nations, called nation X and nation Y, each with 8 missiles. Nation X spread their 8 missiles over two trucks, of the type you posted above. Nation Y, spread their their 8 missiles over 8 "civilian looking" trucks, scattered and well blended. What do you think is a more capable and survivable layout?
In the scenario above, both nations had equal number of missiles. In the case of Iran, there are not many countries out there that have more missiles than Iran and those large number of missiles are spread out in a very survivable and calculative manner.