I'm conceptually in favor of airbnb and its peers. However, in NYC there's definitely an odd dynamic right now - renters are the main proponents of the service, because they can turn around and re-rent their apartments and recoup some of their housing costs (I know some people who are turning a net profit), but I'm pretty sure this is short-sighted. NYC is underserved by hotel rooms (maybe for zoning reasons?), so hotel space trades at a premium to residential space. If apartments become eligible to earn income as "hotel rooms", it's landlords, not renters, that will ultimately benefit - the rental market will reset at a higher rate and we'll all be forced to rent out our apartments when we're not around to make up the difference. I see this already in the form of friends renting larger apartments or paying higher rents because they expect to benefit from airbnb income; that behavior has to be driving up rents. Half my building (literally) is for rent on airbnb, as well as a third of the building next door.
This may be 'net beneficial' economically but I'm pretty sure most of the benefit will ultimately accrue to property owners, not renters.
And of course, although owners may come down hard for liability reasons if they find out about airbnb operations in their buildings, they have every incentive to turn a blind eye: if they can plausibly claim they didn't know and blame the tenant, surely their liability is at least somewhat reduced and in the meanwhile they benefit from rising rental income.