Cash advance is a loan taken out against the balance on a credit card. Usually, the limit of the cash advance is a percentage of the total available balance on the card. Most banks allow users to access the cash at ATM machines using their credit cards. It is important not to exceed the limit of the cash advance since the penalties would be similar to a regular credit card purchase that is over the limit.
Today, credit and debit cards have nearly replaced cash but some vendors still require immediate cash payment upon purchase. Using a personal loan to pay for something so small could be quite expensive and debit cards are useless if there is not enough money in the account at that moment to cover the purchase. This would be a case where a cash advance would be a smarter option. It is also a good idea to only use a cash advance in emergency situations as the interest rate can be very high.