...

Diffuse shading is one of the most common looks in rendering.

Diffuse objects are often dry and unpolished. Think of newspaper, dirt, and rocks.

These objects all reflect light in a wide range of directions from the surface. This means these there won't be shiny or reflective, that which requires something like LamaConductor to add shininess and reflectivity.

Diffuse shading is often the base of many looks for your modeled objects.

...