Simply said, yes, it can. Just because they are easy to make and they are low-tech, doesn’t mean they should be used only several days or months. Basically, they can function as long as you need them. Even if an owner is moving to some place other, he can dissemble his green shack and transfer it to another place. Of course, they are designed for parts of the world where temperatures are high, and there is no winter. If they are the best or the only solution for cold areas, there are several improvements that can make a green shack perfect solution for that specific area. The first is heat isolation. It is easy to make and it is cheap.
If green shacks are used for a short time, then the way how you will place them isn’t very important. On the other hand, if a community or a family is planning to use it permanently, they should be placed as regular houses in the cities. Also, the space between them should be at least 3-4 meters. Maybe it sounds like a ruined space, but growing food beside them is more that possible, so they require additional space.
Interior of a green shack is simple, and it doesn’t offer much, but an owner should pay attention to the placing his things inside. All of them, should be placed so the maximum amount of space is used, and the functionality isn’t ruined. Exterior is less important. Actually, the only important thing is to protect a green shack from the rain and water. A simple paint-job will do the trick.