In pretty much any small city in developing nations, AirBNB is the only viable option. Many of these cities have experienced rapid growth thanks to EU and Chinese loans, but the hotel infrastructure has not kept up. In one Balkan city I visit frequently, I can pay $150/night in a 40 year old Holiday Inn that was condemned a few years ago for structural reasons (then the decision was reversed), or I can pay $15 a night in an AirBNB some poor schlub making $200/month is renting out to make ends meet.
I'm going to choose door number 2 every time. Any time I am given the choice to buy something, especially a higher-quality experience at a lower price, from a human being versus a corporation, the human gets my money.
Just like I prefer Uber to taxis, I prefer AirBNB to hotels. Even Hostels now, if I go into Amsterdam I will pay $35-$50 per night. If there are two of us, the $50 per night AirBNB is our choice.
These businesses flourish because the social contract is broken. Creating artificial scarcity will harm the community in the long run, preventing tourism and limiting the ability of home owners / tenants to make a couple of extra bucks on under-utilized resources.
Whatever this social contract is, I've never signed it, and I don't really recognize anybody else telling me I must abide by this contract upon which I was given no opportunity to vote or discuss.