Good CGI is so realistic that you don't always know when you're looking at it. So, Ironically, CGI artists take it as a compliment when their work goes unnoticed.
But that's no good when you're trying to show off your talents. That's where the CGI breakdown comes in. By peeling away the layers (and them putting them back again) you can show exactly how much painstaking work went making a landscape or object look like everyone assumed it looked anyway - except that they would never have imagined it in such detail.
Here's a great example of a CGI breakdown - and fantastic CGI work by Brainstorm Digital. http://www.brainstorm-digital.com/indexHome.htm
Boardwalk Empire is a major US hit based in Prohibition-era Atlantic City: a time and a place that was ripe for criminality and corruption.