Many people think of it as a pre-paid debit card.
A gift card retains the value placed on it by the consumer at the time the card is purchased. Unlike a paper gift certificate, a gift card may be used for one or more purchases. It is not necessary to refund the unspent value on the gift card. The value stays on the card until the cardholder uses it. It's like having a small billboard for your company in your customer's billfold.