I was talking about people who opt to get a credit card, as against a loan for the actual money they need - without having a card that is paid off and sitting in a wallet/purse with 'free money' on it - along with the occasional limit increase or other enticing offers.
Credit card companies have a number of tricks (and by that I don't mean anything underhand or illegal) to try and get people to use their cards, as they're not in the business of issuing a card with zero interest for xx months and then having people stop using them thereafter, or indeed just paying off the balance in full every month.
I too have been able to pay off the balance on my card every month, using it for the convenience (and security) over a debit card or carrying cash. But, I am sure that more people than not end up using the card a little bit more here and there, and eventually start to pay a little less - and carry over, with interest, some of the balance.
We do have various warnings here too, but I think people either don't fully appreciate the commitment, or seem to convince themselves that they'll be able to afford to pay a debt tomorrow when they can't today, without asking themselves HOW they will do that (such as how the money they earn tomorrow can pay off debts when they need to still pay current bills, eat etc.)