The uses of Specular Maps are:
1. Some surfaces are shinier than others. By mapping a texture to the specular attribute of an object’s material, we create a specular map which lets us to describe how shine appear on objects.
2. Specular highlights show the places on the object where the light sources are reflected at consistent angles; reflections on an object show, among other things, light bounced from surrounding objects.
3. Specular highlights depend directly on the view (camera), not on the position of the light, like diffuse shading does.
4. The size of a specular highlight on a surface makes the surface look either flat or shiny.