Were you under the impression that your credit card transactions are private? If so, I am sorry to burst your bubble. As you will see below, there are actually multiple government agencies that are gathering and storing records of your credit card transactions. And in turn, those government agencies share that information with other government agencies that want it. So if you are making a purchase that you don't want anyone to know about, don't use a credit card. This is one of the reasons why the government hates cash so much. It is just so hard to track.
Any trades in cash thwart the government's efforts to track private exchanes. Rightly so, as no external party has any right to the details of those exchanges.