Just a guess, but I think dehatured EtOH is more combustable or fast burning. Just a guess.

Speaking of denatured EtOH, I always have a soda can stove, water, and my 1 liter titanium pot in my car 3 seasons of the year. I also carry one in my survival kit in the winter when I ice climb or mountaineer.

A buddy of mine tested my soda can at everest base camp ~17,000 ft., and it worked great. I have personally used it effectively up to 14,500 ft.

Burns 10-12min and brings a liter of water to a boil, 170 F at sealevel, starting at RT, in about 8 min. or less. Great item to have. The stove, the fuel (6 ounces or 10 uses), and the pot stand all fit it a stuff sack 3.5" across, 4" high. The big plus is that it only weighs a few ounces without the fuel. I haven't used my MSR "lite-weight" white gas backpacking stove in 3 years- just too dang heavy and hard to light compared to the soda can stove.