That looks like a slick tool. I'm not sure how it alters the laws of physics to keep heat from rising, but that probably has no bearing on how well it works. Around here they use a similar tool called a "pear burner" to burn the spines off of prickly pear cactus. The reach is long enough that you can reach the plant from inside the truck or on a horse if you're not carrying too much gas. Once the spines are off it, the cattle eat it right down. 20% vinegar can be used again and again. If you use it correctly as a foliar spray, it will not directly kill the roots. The near instantaneous loss of a crown may kill the roots on some plants and weeds. It works best on hot sunny days. Be very careful to keep it out of your eyes.