You're confusing revolving credit with a car loan. A 0% APR loan on a car, or computer, or vacuum cleaner is not only a real offer with no strings (most of the times), it's fairly common. You see them offered by either the manufacturer (the actual Ford corporation, not the dealer) or the retailer (Newegg.com), rather than an third-party bank.
The benefit to them is that they sell the car, mattress, or computer today that you, the interest avoiding consumer, would not have bought until next month if you were paying cash. It's not much different than an infomercial offering 4 easy payments of $9.99. Less pain up front makes you more likely to buy now.
Even the credit card companies, contrary to popular belief, are thrilled to have someone like gravedigger use their credit card on everything and pay it off each month for no interest. Don't forget about transaction fees; they may not be charging you, but they are charging the retailer.