USPS scans all your mail. You can even sign up for the service so that you get emails with pictures of the mail that will be arriving in your mailbox soon. Its called "Informed Delivery" https://informeddelivery.usps.com/

The idea that they don't record this information and use it for some other purpose (if nothing else selling this info to marketers) seems rather naive to me.

But yes, we have entered an age of massive surveillance (by government AND corporations) tied to some sort of "social credit score". And yes, we already have the Social Credit Scoring systems in place, they're sites like MyLife and Spokeo. Go search yourself on MyLife you'll see they actually rank you with a score.