I'm skeptical of at least some of the anti-CC agenda behind these articles that talk about how people spend so much more on credit cards. My belief is that some of them (especially from Ramsey) are intentionally misleading.
How many times have many people paid the entire tab for the group having lunch, with the others paying you their share in cash? If I'm one of five at a lunch table who each owe $10, I skew the stats by charging $50 and getting $40 back in cash, though in reality I still spent $10. The study sees one $50 CC transaction instead of one $10 CC transactions and four $10 cash transactions. Think that can skew the numbers just slightly?
How many of these McDonalds transactions were two guys each spending $5, with one guy paying the entire $10 on the CC and his buddy giving him a fiver in cash?
This can show up as one large transaction as opposed to several smaller cash transactions. To the extent that these articles don't even account for very common situations like these which would understandably drive up the average CC transaction, they are very flawed.
Add to that the bias many people have against using CCs for small transactions and the argument is even weaker. I tend not to use mine at all under $10 as a courtesy to the merchant. There may be something to it, but failure to acknowledge these common realities makes me discard the entire study as useless (if not outright intentionally misleading).