You will be able to use the card at WDW restaurants, but I did have one issue when I tried to use mine. When the card is charged at a restaurant, an additional 20% is added to the bill before approving the transaction. I'm not sure if it's the restaurant or the credit card company that does this, but its done to allow for the tip. Ultimately, you're only charged for what you sign for, but they account for an additional tip before approving.
When we were at California Grill, we tried putting our $100 Visa gift card towards the bill. There was a $100 available, but it kept getting denied. After that, we just used the card for other purchases besides restuarants. We then called Visa and were told about the tip thing.