Interesting. Funnily enough, I don't use the gift cards when I cruise. Here since the shutdown, I usually have a decent amount of OBC (plus DH and I both own Carnival stock, so that gives us more). This last cruise in February was an 8 day with 4 days at sea. We forgot cash, so DH charged the room for about $250 in the casino (actually more, but he won it back, so we put it back in to our account). Ended up leaving with $200 charged to my Carnival card to get points towards paying off a charge.