Actually, my card gives decent cash back and it's definitely worth it if you try to put as much as possible on the card. I haven't heard of a debit cash back card.

US Bank used to offer cash back on debit cards; don't know if they still do. ING Direct occasionally has cash-back promotions on the debit card for their Electric Orange checking account, but only for new accounts.

You're right in that credit cards are still useful if you use them right, though. There are certain protections (chargebacks) plus the benefits you note. Credit card companies are like casinos--they give you tons of benefits if you use them hoping you'll go on tilt and waste tons of money. If you're smart, sometimes you can beat them at their game.

"If you're smart, sometimes you can beat them at their game."

Following your analogy, the majority of people are probably better off financially by not going to Vegas at all.

Forget the analogy, this ain't Vegas. All you gotta do is remember to pay one bill on time every month and you're a (small-time) winner.

Oh, and you should make sure you never spend more on your credit card than you have in cash to pay it off; but you should have at least several months' expenses sitting around in cash anyway, so this shouldn't be an issue as long as you have good financial habits.

For an average-income person with good financial habits a 1% cashback credit card is a net win of maybe two hundred dollars a year. Not a huge deal, but the best financial habit you can have is not saying no to small savings.

But this is what the Vegas analogy means: if you follow the optimal strategy while gambling and stop when you've gambled enough to be comped a room, you'll be +EV compared to the normal cost of the room. It's just as easy as paying off your credit card bill every month, assuming similar levels of financial discipline.

Hmm, I didn't know that the comps worked out that way; I always assumed that the value of the comp wound up less than your expected losses even with optimal strategy. Nice to know.

Still, it's a lot easier to remember to pay a bill on time every month than it is to play optimal-strategy blackjack for hours with no mistakes.

The analogy holds, but it's not all that good an analogy since there's a severe difference in the difficulty and the risk/reward ratio. Some things are better explained in their own terms than via an analogy.

The kind of person who vacations in Vegas isn't likely to be someone who makes rational economic decisions about +EV comps, so Vegas isn't worried about offering +EV comps. If you're a rational +EV economic decision-maker, you either don't go to Vegas, or you live in Vegas and make your living beating tourists at poker. Either way, you're not the one being comped a room--more often, it'll be someone who goes on tilt.