Hi there, Shawn!
Thanks for checking back in; I'm glad to help you out.
YES.
Disney gift cards (and
Disney Dollars, available at the Parks) are usable like cash throughout Walt Disney World, at both the Parks and Resorts. The can be used for food and beverage purposes, as well, including at Disney-owned and operated bars. They work like cash, so you can also put them toward gratuities; the total will be drawn down from your balance with no additional fees taken out.
If you dine with another party also on the Disney Dining Plan, simply ask your server for their check. After their entitlements have been deducted, you can then add the gratuity using a credit card, debit card cash, or Disney "currency." You could also use your Key to the World if you attached a credit card to it at time of check-in.
Since the gratuity is the final step in the process, there's more freedom for Cast Members to work with in terms of means of payment.
Please be advised that for parties of six or more people, a gratuity of 18% will automatically be added to each bill. Let your server know in advance that you'll be handling both of those automatic gratuities.
Let me know if I can be of any further assistance, and have a wonderful time!
See you later, celebrator,
-Deborah B.