Twenty years ago, the building design fad was about large, spacious family rooms. The room combined living, dinning and kitchen in an opened fashion, with much glass, vaulted ceiling and no privacy.
The result came down to uncomfortable living environments susceptible to extreme temperature conditions and costly air bills. A situation that would take an engineer to resolve.
Placing rooms next to one another allows for a similar feeling of openness but lets parts of the house be closed off as needed. Those picture windows in the living room can be replaced with a section of wall and an insulated bay window. Creating more rooms also allows for more style and flavor, as well as comfort and privacy. Just add a few French doors and windows in the right place.
Having integrated living space is like building a four car garage to a two bedroom home.