Has my overly frugal girlfriend used poor judgment and taken her money saving efforts too far?

My girlfriend bought all her Christmas gifts for everyone on her shopping list at the same store. This store gave her back "Store Money" that she could redeem for herself for a large % of the value of what was purchased. She then informed me not once but twice, of this while laughing self-admiringly at herself at how cunning she was, boasting that she could now get something for herself for free. I feel that gifts should be given altruistically with the intrinsic reward derived from the recipient's heartfelt thank you and not with a self-serving ulterior motive to extrinsically reward herself.