I think it absolutely could be. As I said in a post above, I've used it once, to stay at a private home (with the family living there) when I traveled to Europe last year and the hotel rates in one particular city were absurd. It was a great experience for me, though of course staying at a private home is very different from staying in a hotel, and very limiting in some ways. For people wanting to do this, "legal" hotels just don't offer that same experience, and I think such a service can certainly be profitable.
However, it's not going to be mega-profitable like Uber or any other well-known tech companies with giant IPOs and huge valuations. And this I think is the problem: greed. Why can't the owners just be happy with something that makes a tidy profit and provides a nice service to people who want a different travel experience than what you get staying in a bland hotel room?
