Earlier quoted context omitted.
Who cares about credit card numbers when you are protected for free and your credit card can be reissued unlike your SSN. I can't believe than in 2015 there's no modern way to verify and protect your identity! There are still so many stupid system relying on your last 4 of your SSN or DoB as authentication!
In Sweden we have a personal number. It's unique to every person but its not secret at all. You use an official identity card or passport or the electronic variant to identify yourself. I'm guessing its some kind of privacy issue behind there not being a similar system in US? Because it works pretty well.
That forces individuals to treat it as sensitive information.