What is the purpose of Deviation Analysis on solidworks 2017

Hello everyone, I would have liked to know if you can tell me what the deviation analysis is for on solidworks 2016-2017 because I see how it can be used but I don't know what it can be used for. Thank you in advance for your help.

This is to use with ScanTo3D.

Here's what the help says:

PropertyManager Deviation Analysis

Use the Deviation Analysis PropertyManager to view deviations between the mesh and other features created by reference to the mesh.

A color display or color vectors show the deviation. Hover over the deviation to get specific deviation values. You can save a detailed report of deviations.