This concept has been around for a long time. Not worth it if you're a rent stabilized tenant with a below market rent and a landlord itching to oust you, or if you're in a co-op and can run afoul of the board.
Not so great for travelers either, even under the best of circumstances. Twenty five years ago, the only time my mother (who even then needed constant access to a bathroom) and my sister (then pregnant) visited me in New York City (for another family member's wedding) I thought I'd save them on a hotel room and found one of these services with a one bedroom listing not in some gummy tenement in then decidedly-untrendy Hell's Kitchen but in a doorman building in a fantastic safe neighborhood on Central Park South where the bedroom was rented out and the tenant would stay in the living room. I thought "How bad could it be?" For years I'd hear complaints about how noisy the apartment was (the bedroom overlooked Columbus Circle, not Central Park) and how the tenant, a hippy-dippy actress, had scheduled some kind of group meeting at her apartment that night so my mother could never use the bathroom.