I've not been to the PH at disney yet, but I would honestly thing anything that close to disney is going to have a gift shop.
My gc says on the front "This note can be redeemed for food, beverage, or merchandise at any Planet Hollywood in the US."
Then on the back it says "good for $25 USD value on food, beverage, meerchandise, tax, and gratuity. No exchange for cash."
So, it looks like we can use it for anything. It also doesn't have an experation date on it.