I suppose it could be used like that. Basically any time you can have two states at the same time, you can use those for layers.
Another example would be for Samus from Metroid. Samus can stand run and jump, but all the while her gun can be aiming in multiple directions and be in multiple modes like missile or gun mode.. Now those things could just be an instance variable, but then it would need to be managed in every single state. With layers you can just handler her gun in its own state machine while her running and jumping is handled in the other.