I too, have been doing that off and on for the last couple of years. I'm not sure but I think I first heard of the concept in a NIK radio interview with John Paul Caponigro. It certainly doesn't work for all images and typically, I find I have to either dial the opacity back some globally, or paint out locally to one degree or another, as it can be a little over the top otherwise.
I've found it to be just one of the many creative techniques that we're now blessed with in the digital darkroom and have found it's certainly worth experimenting with.
Phil