That's what a debit card is, and plenty of people use them.

Many people are idiots, though. They'll use a credit card and pay interest all the time, rather than have the money to buy that TV or whatever before buying the damn thing.

I use a credit card to take advantage of the warped system, though. It gives me several benefits and costs nothing extra because I pay it off in full every month. All my purchases come with a year of reimbursement if stolen, a year of warranty past the manufacturer warranty, and cash back points. I have gotten thousands of dollars over the years for using a CC. Free money.