If you're wokring to improve your painting, reference is a necessity. The question is not "should I paint from reference?" but rather "What reference makes most sense for this piece?" This video looks for painting reference in an unusual area: visual effects test renders.
If you're looking for the search terms mentioned in the video, here's a good starting point: Global Illumination (GI), Ambient Occlusion (AO), Caustics, Photons, VRay, Mental Ray, and Radiosity. Search any of those along with "test render", and you'll have some fun reference materials.
The anatomy reference was found at onlinelifedrawing.com