How about this? As I mentioned, rice dishes are made in a small wok which have been seasoned. The seasoning prevents the rice from sticking to it and are cleaned carefully without washing in water. The aluminium pans are used for curries and are then placed in the sink and soaked before using a wire brush and chemical to clean off the residue of the cooked curry.....often solidly caked in some areas. You coulnd't do that to a seasoned wok. It would require to be seasoned again. And if it isn't seasoned, then the rice etc will stick to it.