It depends on how humid is each room. Some room have better airflow and somehow is not as humid. For rooms where there is a bathroom nearby/ just outside, chances is that the moist will get into the room. I've been using dehumidifier in some rooms and I can feel the difference. For example, the floor don't have some sort of sticky feeling, and the air feels somewhat lighter/ cooler. Even the air conditioning system don't have a musty smell.
For living room, I think it is pointless because it is too big. To dehumidify the living room, you need some very high powered dehumidifier which will hit your power bill hard.