>>796789It is a matter of time. Two stoves, using the same amount of fuel, will have different lengths of time to cook the food if one is more efficient than the other. That can shave 2 to 20 minutes off the time it takes to cook the food depending on the length of time to cook and the % difference of efficiency between the two.
>>796792Packable wood gas stoves can be pretty small, but those are mostly the forced air kind. The non-forced air wood gas stoves usually have a tall chimney.