I can picture one in my backyard, equipped as a sauna, that would be cool. Well, hot, but you know what I mean.
It would have to be delivered to me complete, though, I can't imagine being able to construct a kit with so many strange angles.

I don't see the reasoning behind making it such an odd shape. Seems to me to be too difficult and costly to construct for its intended purpose.

The odd shape is what makes it stand out. If it were just a standard house-type shape it would look like a garage. I mean, that's cool and all, to have additional living space; but to have it look odd makes it really stand out. Plus they look wicked cool from the inside.