Just to add my experience: I did 1 night FHR for the $300 credit, followed by a stay of 2 FNCs. I was met with quite a bit of resistance using the Aspire credit, Biz Plat credit, Surpass credit, and 4 Hilton gift cards (Amex), as the woman working said they were not supposed to allow the gift cards because they weren't the right "type" of Amex. In the end, she did take them but it took about 20 minutes for the whole ordeal. 🤷🏻‍♂️