Shipping containers are great for packing full of stuff, but dreadfully proportioned for living space -- less than 8' ceilings (before insulation and finishes); less than 8' wide (before insulation and finishes); and forty feet long with a door at only one end (horrible for circulation and functional zoning because you have to walk through one space to get to another).
Just because a shipping container worked for Stewart Brand when he put together the Whole Earth Catalogs, doesn't mean they make good habitable spaces. The length was useful for laying out lots of pages in a production line and the steel walls allowed him to use magnets for 'pinning up' pages. These are not features particularly relevant to most activities including software development. [See Brand's How Buildings Learn].
The predominate feature of shipping containers is that they make great archiporn images of the sort shown in the article - a high road building masquerading as a low road building (something Brand also talks about in How Buildings Learn).
BTW, it's probably a summer house given that it has no garage, which is even harder to imagine as a design decision for a Maine winter.