Not sure I understand. Do you mean from the point of view of the merchant? From the point of view of the consumer, I don't think I've ever done anything differ

Not sure I understand. Do you mean from the point of view of the merchant? From the point of view of the consumer, I don't think I've ever done anything differently in regards to tax paperwork with regards to differences in method of payment. Even from the merchant's point of view, I would imagine credit card payments are easier to keep track of for documenting purposes. Unless, of course, your intention is tax evasion, which I know quite a few merchants (including family) do with cash.