IR rolls old school. no cc's, no wallet, not even one of those money clips which are becoming trendy. cash in a roll. big fazools on the outside.
i think IR's point, which many studies have indicated, is that credit cards lead to excess spending. it might be impossible to avoid them in this day and age, but to the extent you can, it just might provide far more rewards than you earn back. if you give a person a $5 bill and credit card, then send them into a store to purchase food, they will often come out with items that cost under $5. send the person in with only a credit card and its not surprising that they spend far more. its not a surprise the national savings rate has plummeted as cc use has become more commonplace.
the credit card companies are not in the business of losing money. it's no different than any deals a casino might offer you in blackjack -- insurance, even money if you have bj and dealer showing an ace. they wouldn't offer it to you if it wasn't more profitable for them. credit card companies know (whether you realize it or not) that rewards will induce you to use your cc more often and that whatever rewards they're giving you ultimately helps their bottom line, not yours.
having said all that, there are some people who can and do game the credit card rewards and that probably includes some of you here. for ex, arbitraging balance transfers has been discussed here before. more power to you guys, but overall its probably more of a win-win for the credit card companies than the avg consumer.