Mannequins are like Greek and Roman statuary. They don't need to be dressed, nor do they require a name. Like many works of art, they exist to be seen, at times to be admired, and always to be photographed by the likes of me.
Their main purpose, of course, is to attract attention, and sell. If a store owner has a shabby, disheveled mannequin representing him and his wares, then the public may assume that what he is selling is equally impaired.
In the photographic world, however, there are no clothing or other items for the general public to purchase. So the scratches, bruises, gouges, etc. become a tool for the intended content of the artist.