summary
gift cards:
have an expiry date
can only buy from that chain of stores
only worth a nomimal value ($20 giftcard is $20)… if a $20 giftcard cost $18 then there would be no problem
money:
no expiry date
can buy from anywhere
so what use are they again?
That's precisely why many people buy gift cards. Also, it's somewhat gauche to give money as gifts so cards are a good alternative for the unimaginative gifter. Kids can also purchase gift cards with cash to add credit to their iTunes or Nintendo accounts without a credit or debit card.