Compared to cooking with gas, electricity, wood, or charcoal, the power is free and non-polluting, the food often tastes better and is more nutritious, the indoor space stays cooler, and because foods will not burn or scorch in most box cookers, the pots are easier to wash.
Compared to solar panel cookers, box ovens have more heat stability. Although some solar panel cookers may heat foods more quickly under good sky conditions, when too much haze or too many clouds spring up, foods can lose heat rapidly. A box oven and the food inside will lose heat if sky conditions worsen, but not nearly as rapidly as in most panel cookers, so there will be less heat to regain when the clouds blow away or the haze thins. A box oven also has the potential to be a good retained heat cooker or warming oven, with the addition of blankets or pillows or other insulating materials tucked around and over the pot(s).
Compared to a parabolic cooker, a box oven is slower but does not present danger of fire or smoke or serious burns.