I got the Eco-Billy as a wedding present, must be 25 years ago now. Everyone got a kettle didn't they?
We used it a lot on day trips as you could get a hot drink in a few minutes for little effort.
I'd turn it upside down, stuff it full of twigs and leaf litter, put it on the ground right way up, add water and light it. That was usually enough to boil 1.5L of water. If we were staying longer, then drop some bigger sticks down the chimney and when you take the kettle away you have the basis of a camp fire.
It doesn't get much of a run these days, I mainly use the butane or dual fuel stove with a stove top whistling kettle. The bush kettle doesn't work very well on a burner. After moving to Qld, winter exploring isn't as cold either, so you're generally looking for a cool drink, rather than a hot one.