<prompt> Human: There are two parts to this:1 Why exactly is it that a payment mechanism is connected to a particular financial instrument the way cards are tied to a line of credit?2 Why do people haveuse them? If you have any savings, why wouldnt people just spend that. Presumably if you are without savings, why are you living beyond your means? Why dont people change their lifestyles. It seems that these more than a home loan or car loan, the purpose for which is pretty straightforward, exist only to temporarily sustain an unsustainable lifestyle. I just dont understand why beyond a huge emergency why credit cards would exist as a thing.  <response>: Several reasons to use credit cards and pay them off each month. It puts a layer of security between your actual cash and the transaction. If your debit card information gets stolen, you are out the actual money until and if it gets sorted out. Credit card companies generally take on the liability for fraud. Second, if you can qualify, you can get great rewards. Ive received thousands of dollars in cash back and free flights over the years from using cards with rewards. I have never in my life carried a balance or paid a penny interest to a credit card company to do so. Some cards have fees, but if used correctly the fees pay for themselves. 