Housing is a service, and landlords, who provide this service, take principal risk as well as pay for maintenance, taxes, and other costs. Why should those who provide such a service, such as housing, not earn rent for their efforts and risk? Developers buy properties in bad neighborhoods in the hope of improving and renting them, but without profit, where is the incentive to invest? It's a two sided-equation: for services to exist, there must be an incentive for the other side to provide said service, and that incentive is profit.

Regular apartment rentals often lock renters for multi-month contracts (due to difficulty, length, and expense of the eviction process, in which landlords lose money during the lengthy eviction process, when a renter rents for a single month and does not leave after not paying); air BNB, although it's more expensive per night, doesn't have such long time commitments for renters.