using those gift cards can save passengers 10%, and this should not be so difficult. I can use them on CCL to pay for the cruise, excursions, cash on board, drink pkg, etc. The CS rep I spoke to simply did not understand gift card vs. certificate. She quickly grew frustrated and told me to use it once on board. I won't purchase any unless I KNOW for sure I can use them. I'll call back and see if I get a more knowledgeable person.