And when you buy that saw you've been eyeing for three months and get it home and the thing breaks coming out of the box - and you don't like any of the other models they carry... you're stuck with a $50 piece of non-refundable plastic.
I hate gift cards. I would only take advantage of this if I was buying something that I /know/ I'm never going to bring back, such as custom mixed paint.
(And it's not even a NICE credit card weight gift card like Wal-Mart and every other company has lying in giant stacks around the store nowadays. Just a flimsy piece of nearly paper-thin plastic. Heck, Wal-Mart even has holographic and lenticular cards. Wal-Mart's plain cards double as glue spreaders once they're empty, too. Or I suppose you could just grab a stack of blanks)