"The best way for an artist to envision the poitiness node is as follows.

The pointiness node creates a black/white map of a mesh where black/white is infuenced by a few things, the most important of which is the angle between two faces. Flat surfaces will appear as a flat grey, obtuse angles (corners of a table) will appear white while acute angles (the inside corners of a box) will appear black.

An artist can then use this map to enfluence other textures and materials, most notibly the fac socket on RGBMix and Mix Shader nodes. For example, for the metal in this mechanicle arm, I have three shader groups:

Painted Metal Raw Metal Dirt

A color ramp is placed inbetween each Poitiness node and the Mix Shader it's plugged into, the color ramp is tweaked to leave most of the model black, with the edges white. This allows me to give the whole object the Painted Metal shader group, then mix the Raw Metal into the sharp-corners, where the paint would wear and chip the most, and the dirt into the hollow recesses, where dirt and grime would clutter. All this is done automagically, I can skip the normally tedious task of manually painting one material over the other where wear-and-tear would occur.

It should be noted that this may require some slightly modified modeling techniques for some modelers. A prime example in this piece is the section near the right, where the large sphere is intersected by the + shaped axel. Instead of creating a seamless mesh here, I chose to build a basic extruded + and let it clip through the sphere. Since there is no actual joining of faces between the sphere and the +, Pointiness can't create a white-spot in the crevice between the two, thus allowing it to remain unrealisticilly free of dirt.

TL;DR creates a convenient mixing map to allow the artist to automagically create wear-and-tear and dirt-clutter an an object using only material assignment."