We can say that the moudlar prefabricated housing industry was started from conversion of used shipping container to a house. It's too expensive for a country to ship empty containers back to their origin. In most cases, it's just cheaper to buy new containers from Asia.
In 1950s, the U.S. Military started developing and using shipping containers as temporary camp. Nowadays, more and more people like this concept, especially young generation. Brand new container house is made to be combined into large permanent building, we all it PPVC (Prefabricated Pre-finished Volumetric Construction).