I was hoping this was going to talk about the increasingly trendy open kitchen concept in homes, or more specifically answer the question: why have kitchens traditionally been separated from dining areas in the first place? Unfortunately, the article is about restaurants.
Smell. To keep the smells of cooking from overwhelming the rest of the house. In the process of building a new house and it will be a separate kitchen. Well, technically, a wet kitchen that is closed off and a small dry kitchen connected to the dining area for dealing with things that aren't strong smelling. This setup is pretty standard in here in Asia.