Why is it important that the weight is shown on a food label?

There are many answers o this question

just think,

for example, a truck driver is asked to load a bunch of tomato crates onto his truck, which can only carry 1 tonne, how is he gonna know the number of tomato crates his truck can carry?

They have to give standards to everything to make life easier, without a measured weight, people may not get equal amounts of food, to put pricing, and some people may be in diet so extra amount of something might harm them ... there are so many reasons