On our last two cruises, in the casino, we were rated and received some pretty good rewards. To me, this is something fairly new.
They also told me to book through their casino marketing on Carnival. I've done that and received a decent discount on the cabin, cash to gamble with, small gift in the cabin from the casino and free drinks in the casino after getting X number of points.
We gamble anyway so this is a nice perk for us.