Mysteries of the Multi-Store Gift Card

I've seen a few of these gift cards that you can spend in any shop floating around. A gift card is already a pointless thing from the consumer's perspective. The only real reason behind them is to satisfy the requirement that you purchase goods for the annual consumerism events. It still makes sense from the shop's perspective. People who buy giftcards are spending money in the shop that they mightn't otherwise. Some of the money is likely wasted when the recipient of the card doesn't quite meet the face value, or they will be prompted to spend extra to go over. None of these benefits exist for a multi-store gift card. I would assume the money is just held by the card company until its spent at one of the supported shops. It offers nothing for either party involved. It's just money but worse. Why do we have these?