In fluids like air, heat transfer is dominated by fluid flow, in the form of convection in the case of cooking over an open fire. It's useful to think of a pie

In fluids like air, heat transfer is dominated by fluid flow, in the form of convection in the case of cooking over an open fire. It's useful to think of a piece of cookware as a kind of radiator, because that's essentially what it is. Heat is transferred to food by direct contact, but also by radiation. Pots and pans are shaped perfectly to maximize both radiation and conduction by contact, and thus they experience a very high rate of cooling. This means that if you want evenness of heating, then high thermal conductivity is necessary in order to keep up with the heat loss.