Many cities have really great neighborhoods near subway stops with no good hotel options. Think Williamsburg in NYC, Mission Dolores in San Francisco, and so on.
I think the value-add of Airbnb in cities is the neighborhoods you can stay in.
Agreed. I got a very nice studio apartment in Chicago near my friend's house in the Lincoln Park neighborhood when I went there last year for his 50th birthday party. There are no hotels around there, and it was dramatically cheaper and more convenient to stay in that area vs. downtown, where all the hotels are.