Whatever the case, despite the existence of the options you list, Airbnb's are still popular. There's clearly some significant differentiator between them and an Airbnb.
But there is a psychology to it that is, as you say, hard to pin dow. A hotel that has a random assortment of plates and cutlery in the kitchen (like my last AirBnB did) would feel cheap and tacky. The AirBnB didn't.