Great post! I agree, it depends on how you use your card. I also would rather carry a credit card instead of a wad of cash. With the price of groceries these days, I’ll still have to spend the same amount I would spend with a credit card, but I don’t have to carry $60-$100 with me to the store. And since I pay my balance in full and on time each month, I’m not hurting my credit score. And yep, I earn points/cash back with my purchases, so it’s a little extra money coming back to me.
In the article you linked to, they discuss that you don’t see the money leaving; I disagree, at least for me. I look at that register and cringe almost every time seeing just how much groceries and the like are costing me. Granted, if I go to the mall, which doesn’t happen often at all, I might spend more than if I only carried cash, but since it’s hard for me to get to the mall, I end up doing all my shopping at once (it’s more efficient that way, instead of going out all the time to shop). And when I’m shopping, I mostly just buy necessities anyway.

Sorry for such a long comment! Great blog, by the way!