I think they`re nice for detail works. Like some toy cars on the ground. You don`t want to use 3000 poly cars for that
This depends on the platform. I could make you some photos from games like L4D2. I am always wondering how they can use so much polygons for pipes, furniture or little details like a bunch of teddy bears at the ground. There is a map where you walk on a detailed roller-coaster. Even some kids carousels use quite detailed vehicles in large amount. There are bridges and highways with tons of parked cars and other details.
But dont try this on a mobile phone
It is amazing what a good scene management allows today.
