I think it's a nice gesture on the part of B&N. No, it doesn't excuse slipping dates and not having enough supply to meet demands but it does demonstrate willingness on B&N's part to admit they could have done a better job. No one is holding a gun to their head and forcing them to give away $100 gift cards.
That said, it is just an e-reader. While my wife and I are enjoying our Nook, I'd have no problem getting $100 back and waiting 30 more days. The Nook doesn't cure cancer, enhance my daily life in any significant manner, or make the air cleaner.
It's a consumer electronics device and nothing more.