It’s a cleaner burn with far less smoke and better combustion, gives off more heat, needs less tending and uses the embodied energy in wood more efficiently than the tipi-esque fire method.
As an added bonus, the first time you make a fire like this in front of a ring of uninitiated folks, you exist in a ring of utter skepticism. Which makes your rockin upside down fire all the better when it works beautifully.
Heat energy actually radiates equally in all directions from the point of combustion, not just upwards (it’s the displacement of gasses as they expand that sends hot air upwards, not the actual heat energy itself). So once combustion of the top layer of your upside down fire occurs, the heat energy is radiating down as much as it is up.
This in turn means that the wood below the combusting material is getting well heated before it catches fire, which in turn facilitates better and more complete combustion of the wood below when it does catch fire. And more complete combustion means less smoke.