I'd want to hold onto my money until the deadline in case anything happened with the cruise line prior to my sailing date.
We had the Big Red Boat booked once with Premier Cruise Lines (years ago now) and the line went bankrupt soon before my sailing date. Fortunately, we paid by credit card and did get our money back, but all those who paid cash were basically screwed. Even though we did get our money back, we still had red-tape to go through with the CC company so was not fun to deal with.
That is the main reason why I never pay until the deadline.