This shader was developed to change color and texture based of elevation of an object.
This was for situation when a single asset/prop is modeled. That one model is then shaded and is duplicated (without being able to individually change the texture/shader for each of the duplicate), and then each of them are placed in different elevation.
Imagining we only have one geo, that is called 'glass A', shading artist can only use a single ramp node from white (bottom) to blue (top). Without the set up, all the glass A in the left has the same gradient ramp due to the fact that all UVs for the glass A are the same.
The picture on the right shows how the same geometry can have different texture on them base on their elevation (in this case, a ramp going from white to blue).