Here's my favorite thing: DH and I are natural savers. We tend to spend very modestly at restaurants, ordering less expensive things and splitting meals. With the DDP, I love going into restaurants and ordering exactly what I want to eat, with no regard for the price. It's really fun!
It probably doesn't save us money, because if we didn't have it we'd figure out how to eat frugally. But it wouldn't be as enjoyable.