Makes sense to me.
I also had a large dent in a bumper cover caused by hitting a porpupine (the impact made a basketball sized dent in the lower left corner but didn't crack anything, and pushed back far enough to split both inner fenders) that I removed by heat-gunning the back of the bumper until it sprung into shape.
I'll have to show this to my wife. A few years ago I had a '91 Firebird that had a series of shallow ripples near the door handle area (most 3rd gen Camoros/Firebirds get these as they're made of flimsy metal). I took an old hairdryer and a cloth with an icecube to do something similar to that video. Wife though I was crazy. It helped a little. The co2 stuff is the way to go I guess. Maybe I should have got a patent on the idea...lol