Often Snoop it's used to create user controls and apply changes to the UI, one feature that can be useful is measuring.
An example can be found in this application (PixelZoomer http://pixelzoomer.com/) that allows the used to take a screenshot of an image and zoom in as well as having handy selection tools that allow to measure the pixels.
In this case the Zoomer could have this feature giving the user the ability to measure the pixels on screen or sample colors like the original PixelZoomer app.

Thank you!