I didn't quite understand the transition between the model & the real . . . house, Journey.
The important thing was allowing light in but somehow it looked like they turned it around to where the light was supposed to come thru the entrance. I must be mistaken.
The best scenario is that light comes in the bathroom and over the bed.
Could it be that the under 30" part is in the bedroom? With better stair-climbing skills, I think I'd be okay with the stairwell being only that wide but even a living room sofa is wider than 30". And, to have to crawl across the foot of it . . . well, I guess it would be doable. Criminy! I wouldn't be able to have any arms on my over-stuffed chairs!!
DD has been talking again about buying a house. I'm all in favor of it but I would so much like her & SIL (& Garbanzo) to have a new house. And, it can be small . . . This from a guy with beyond-code structures on his lot -- I'm in favor of "going up" with smaller. A small footprint with spaciousness around the home is the route I would go and might yet go in my life & times.
No, Poland's Narrowest House wouldn't be for me but I can see an open interior and high ceilings as going well with smaller rooms. I've only a couple times lived in houses with a 2nd story - I prefer them!
Steve