What do you mean be "store longer"? I've stored average American eggs in the refrigerator for multiple months without a problem (I only use them on the rare occasion that I bake something).

I am under the impression that European eggs are not refrigerated. My understanding is that once you refrigerate an egg, the membrane separates from the shell, requiring that you continue to refrigerate it, as the egg is no longer properly sealed. Since American eggs are refrigerated to begin with, you need to continue refrigeration.