It is mandatory for the manufacturer to make an affirmative claim as to the cholesterol and trans fat content of every food product sold in the US, along with several other items. The manufacturer is only liable for what they actually claim; this labeling standard forces them to make certain claims.

With the labeling you describe of the EU, I could look at every item in my pantry and refrigerator, and not realize that my diet is entirely missing any source of vitamin D, for example. If nothing in any of my labels even mentions vitamin D, I might not even realize it is something I should be looking for in my diet.

When every single item in my diet affirmatively claims “Not a significant source of vitamin D”, it’s a big clue that I’m not eating right.

There is a distinct difference in liability between “accidentally” forgetting to include the sodium (“salt”) content of a product, and affirmatively claiming it has no significant amount of sodium.

When I’m on a low sodium diet and a soy sauce manufacturer fails to list its sodium content on the label, I bear a large part of the responsibility. It is common knowledge that soy sauce is usually extremely high in salt, so I can’t reasonably claim their mislabeling was the cause of any harm I experience. But, if they were to affirmatively claim “not a significant source of sodium”, I’ll own their asses.

Mandating claims of these specific, important nutrients certainly does add meaningful information.