This is a post by Cat McClintock on PTC site.
In industries where form matters as much as function, designers need freedom to explore new shapes and surfaces. Traditionally, this is done with cardboard, clay, or other physical materials that designers can mold to quickly convey the look and feel of their ideas.
Of course you can do all that with CAD software now, saving time, money, materials, and even space. But not everybody has eagerly embraced the technology.