I'm a bit confused with the wording of the Hlton Gift Card terms and conditions.

"You can redeem a Hilton Gift Card when dining at one of our on-property restaurants, exploring our retail shops, playing at one of our golf courses, relaxing at our spas, or for any charge to your room portfolio."

So no doubts about that you can use it at their restaurants etc, but can you pay for the room with a gift card? I know you can't reserve a room with the gift card, but provided you use your credit card for that, why not use the gift card for the payment,at check out?