We buy GC's at BJ's, put our CC on the room charge privileges, use our magic bands for purchases, then around every 3 days, we take our GC's to front desk and pay off balance.
You may already know this, but we combine our GC's, usually 2 $500 cards(they limit you to $1,000 per card). By combining cards, it keeps you from having so many to carry on trip, plus, it helps CM's to not have to put so many cards through at one time. Just a nice gesture to help them and also shaves off a few minutes to allow you to get back to having fun!