Casinos ask us what a player's bankroll is when we submit a comp reservation. They want to know, how much is this person planning to budget to gamble. The casinos, as a rule of thumb, like to see three to four hours of play on average per day. 

Why it's important? So let's say in an unfortunate situation, you book your trip and say your bankroll is $5000. Within the first 2 days of your cruise, you have terrible luck and blow through your bankroll. So then it's very likely you're not going to play for three hours per day if your bankroll is all gone in the first two days. The cruise line can look at your bankroll and know that that's why you stopped playing.

The cruise line, especially with a new player, want to know the bankroll just so they can know what to expect, and also use that information when they're deciding what level comp to offer.