Explaining and armature more in depth.
Wikipedia has a really good definition of the word, basically saying that an armature is the skeletal structure of a sculpture. Provides stability when dealing with soft materials such as wax or clay. Which to my knowledge sounds to be true.
I use them along with my sculptures because it is a useful way to sculpt, making it easier for the sculpture to stay intact when you are sculpting.
By adding it to the baby stomach like I always do, it saves me on polymer clay and for some reason it helps when you are curing it as well.
By adding the armature it creates stability when I am still working on the sculpture and by adding some aluminum paper saves on the sculpture material. In this case is (polymer clay)