Volume is too imprecise. It can vary. E.g. flower. 1 cup can mean a lot based on how rough the ride is from the factory to the store. Salt & sugar have same is

Volume is too imprecise. It can vary. E.g. flower. 1 cup can mean a lot based on how rough the ride is from the factory to the store. Salt & sugar have same issue. Based on grain size volume can differ while weight (and thus cooking properties) are maintained. (Yes, you use big chunks of sugar for Liège waffles, but that's an exception).