I can't imagine a scenario in which I'd prefer an AirBnB for business travel. But here's a scenario that AirBnB was a perfect fit. My daughter is a cheerleader and we sometimes have traveling competitions. There are some families on her team which we're friends with. Rather than everyone getting a hotel room we rented an entire house on AirBnB. Each family got their own room, the kids got to enjoy being together, and we had a default location to just waste time watching TV or whatever all together between competition events. We ended up cooking out at our AirBnB location. It was really great for this more casual travel experience.

Absolutely. And, as I said in another comment, the marketplaces for renting vacation homes, houses, etc. was very fragmented and generally not very good until AirBnB came along. A lot of their business still depends on sketchy host behavior but there was clearly a legitimate need for a better service.

Also, in cities, I'm not sure I even want to spend enough time in wherever I'm staying to have a memorable experience. The city is the experience, not the place I'm staying. Not that I hang around where I'm staying most places but definitely not in cities. Or if I do, it's because I'm working :-/

With regards to non-business stays in cities, I'm more than happy to use AirBnB if I can simultaneously save money and support a small business. I've used AirBnB for beach vacations before and it worked out great for that as well, equally a scenario where hanging out at the house wasn't desired. We were at the beach all day.

It really boils down to how long you're staying, and how convenient you need your check-in/check-out experience. I did get Airbnbs when I was going to conferences for work and it was awesome (one of them was in an amazing house in the middle of Zurich with two other crypto homies).