I've never stayed at an Airport Bn B, but I've stayed at various ones on vacation. I imagine the difference is that people stay there as they are just passing through for a day, or maybe longer if they are visiting the area.
However I've never seen one that looked anything like that.
I would imagine the owner is less interested in being a host and providing a pleasant stay for people than just doing it for some extra money. Imo
I may be misunderstanding your post, but just to clarify: an AirBnB isn't actually a "Bed & Breakfast" accommodation (edit: I should say, isn't always an actual "Bed & Breakfast" accommodation. I'm sure there are some actual BnBs on the site.). There are several kinds: some are entire houses/apartments/condos that are only used for vacation rentals. The owner lives elsewhere and rents it out, and it's empty if no one is renting it.
Some are nothing but a couch or a bedroom in someone else's house. If it's a room, you get the room to yourself, but the owner/host is there. You share common areas like the kitchen, bathroom, and living spaces.
Some are a separate part of a house, a small apartment-like space either in the basement, or attic, or beside the house. The owner/host lives on the property, but the space rented is completely separate and private for the guest.
I'm sure there are other ways it is done, but these three are the basic situations.
All of these rentals can be almost anywhere in a city, from a terrible neighborhood clear up to the fancy beachside accommodations, and the prices you pay reflect the area as well as type of space you're renting.
This particular homeowner apparently lived in his house and rented out one upstairs bedroom and one downstairs bedroom through AirBnB, and the guests would share kitchen/bathroom/common living space with him if they were both there at the same time. It looks like he rented it out for around $30/night, which, if he rented out both rooms even half of the month, he'd be able to bring in an extra $10K+ every year.
