From my experience, it does make it easier if you need to compare similar foods.
For example, I want to buy a yogurt with highest amount of protein. Serving sizes may vary between 150 and to 500gr. With standardized labels it is very easy task.
In my country we have calories listed for both 100g/container and nutrients are always listed for 100g and sometimes for full contaiber. I almost always use 100g part.