we did the same on a cruise a few years ago, it was fine except for the weird way they work the charges, so what happens is, they 'test' the card with a charge when you spend on board,,so that shows on your room telly, then they refund it, then after you've been home a week they charge the final total! it was very difficult to keep track as we went along but it all worked correct in the end. I did end up ringing celebrity to clarify what was going on so they explained the process. It's fine, just don't be surprised when it seems a lot of to and fro!