Ahoy, Kaylene!
Welcome aboard the Disney Parks Moms Panel! The answer to your excellent question is YES! Disney Cruise Line does accept
Disney Gift Cards to pay for any of your onboard account expenses including gratuities. I always use Disney Gift Cards to budget for our Disney Cruise vacations, Kaylene. I pick them up while I'm shopping at my local grocery store and have a nice stash accumulated when it's time to set sail. The Disney Gift Card website allows you to combine up to $1,000.00 on one card so a few days before we leave, I gather up all my cards to put them all together. I label the card that has all the Disney money with the exact dollar amount on the back with permanent marker.
Kaylene, I typically just have the Disney Gift Card funds applied to my account once I'm aboard (gratuities are charged during the cruise unless you want to prepaid them ahead of time). Guest Services will take the card at any time, although I recommend sooner than later since the lines are usually long the last night. I always keep the Disney Gift Card in the stateroom safe after I've had it applied to my account just in case I don't spend the entire amount because any amount unused can be placed back on the original card before you disembark.
I encourage you to start purchasing your Disney Gift Cards as soon as possible. They really do help you budget along the way. If you have any other Disney Cruise Line questions, please write back!
Have a magical day!
Nancy