I ordered them in advance once, and they were delivered at dinner the first night. They were not worth the small savings for a couple of reasons. One, you had to remember to take them with you--the S&S is easy to remember anytime you leave the cabin as it's also your door key. Two, depending on who the server was is whether I actually got the drink I wanted without a big fuss as to the price. I'm a wine drinker so technically the coupon doesn't cover my drink as a glass of wine is typically $5.50+.
I came home with some of them, and eventually gave them to a friend who was cruising with Carnival. And, I haven't purchased them since my first Carnival cruise.
Enjoy your next cruise!