Disney gift cards can only be used at locations owned and operated by Disney, with the exception of the gift shops in the World Showcase. So no, you can not use a Disney gift card there.
Are you referring to the store at T-Rex restaurant at Downtown Disney where they can build a dino? I believe they DO accept Disney gift cards. The restaurant definitely does, so I don't know why the store would be any different.
This isn't true. Most of the locations in Downtown Disney, and even some of the resort restaurants are owned and operated by third parties and just about all of them accept Disney gift cards. The only places that don't are some kiosks, and kiosks that don't accept cards at all.
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