One reason why you may want a container is because it is a movable structure. That means that you do not need a building permit. Acquiring a building permit requires at least a class 5 road. This is the case for New Hampshire. I don't know how representative it is though. Also this not uncommon when for larger lots, but I'm not really sure if there are differences from lots as small as 2 acres.
If that were indeed a hard requirement, it seems like it would prevent a farmer building any structure within his property that's not adjoining a public (i.e. Class V) road.
And indeed the planning board can make an exception:
A private road, but as with Class VI roads, only if the governing body, after consulting with the planning board has adopted a policy allowing building on that particular private road, or portion thereof, and then only if the owner has recorded a notice in the registry of deeds acknowledging that the town is not liable for maintenance...
So I would think that a farmer that wants to build a storage shed on the far side of his field would be able to get a permit as long as it's accessible by some private road (even a class VI dirt road)
Right, the governing body can make an exception for a particular private road. And in that case, you would be able to apply for a building permit. There are also provisions for exceptions in RSA 674:41 that would cause excessive hardship or practical difficulties. So it seems that the law has been made so that a local governing body has the discretion to made a pragmatic decision. However, this all assumes that the local governing body would indeed grant such an exception and that the land owner believes it is worth to effort. In the case of your hypothetical farmer, it is probably worth the effort. However, if you have a 2 acre lot and want to put a farm in a box on it, you might be happy to simply avoid dealing with the governing body and just plant your farm in a box on your lot and get to work.
I guess the first reason is that I was providing an answer to question about why would you want to use a container. My answer comes from personal experience in New Hampshire. I mention New Hampshire specifically because I do not know how general that situation for the rest of the US or other countries. However, it seems reasonable that they may be equivalent restrictions in other place, thus providing a reason for why a container may be desirable.
Secondly, the project is not being marketed for specifically for under-developed countries. In the linked article they do mention their experience in Kenya and that one of their target markets are governments to support development projects or refugee camps. But they also state that they are targeting individuals in the US. Also their website makes it clear that under-developed countries are not the major focus.
