For what it's worth, I did try the stove with a can of Sterno (2.6 oz size, Ethanol gel).

After 20 minutes, there were definitely some bubbles at the bottom of the cup, but it would be a stretch to call it "boiling." At best, the water was maybe hot enough to make tea or coffee.

So I can confirm that Sterno is not a good choice for an emergency stove of the simple stand type.