Tell us about yourself!
What they showed there was not some random mesh, it is actually intended for grilling. You buy that when you want to grill small vegetable or fish and don't want the small pieces to slip between your normal grill racks. They just cut it down to slightly bigger than the pot diameter.
We use heavy duty aluminum foil when we are cooking food directly on charcoals. The normal weight stuff doesn't work - you are right it can even catch fire if you are using a wood campfire. But the heavy duty stuff works out quite fine. Probably single use. I also probably would have been tempted to keep that hole in the bottom to increase air-flow on the fire...but then you do have a hot-ash situation under the pot.