I am intrigued! We have a lot of both Hilton and Marriott points, but I never realized I could book a cruise through either of them. I know we wouldn't have enough points to pay for the cruise, but I love the idea of earning points by booking the cruise through one of them. My concern would be if going that route is basically like booking through a TA. Do you turn over all control to them, have to go through them to pay, etc? I just noticed the other day that Delta has a similar plan where you can earn miles by booking cruises through them.
I would hate to give up that control unless I was actually going through a real, live TA that I know and trust. We have a TA that we work with sometimes and I love her, so I don't mind handing her the keys, so to speak. I wouldn't want to do that with a big, faceless corporation, though. I just wonder how this all works.
(and sorry to derail your thread!)