Please do not take this the wrong way, I just want to helpfully provide another point of view for you, or anyone else looking at the cruise, for the future.
I don't know what cruise you picked, so I just picked one in April (the 7 night Eastern Caribbean). It is 207 points per adult for standard inside stateroom + $95 transaction fee, total 414 points + $95. If those were all BLT points you paid $4.50 x 414 points = $1,863 + $95 = total cost to you for cruise $1,958. This cruise is currently selling for $3,034.24 for the same stateroom for 2 people. So you saved $1,076.24 from the retail rate by using points!
But, if you were to rent your points out with David's at $11 per point, that would net you 414 x $11 = $4,554 - cost of points (414 x $4.50 = $1,863) = $2,691 "profit". Then buy the same cruise for $3,034.24 = total out of pocket for you = $343.24
By renting and paying cash you only "spend" $343.24 vs. $1,958 (or savings of $1,614.76).
Now, this means that you have to feel comfortable renting your points out. Going through David's is fairly safe and you don't have to worry about much. You just get your $11 per point. Another consideration is you don't get all the cash up front from David, so that could be an issue. On the plus side, you have more flexibility when paying for the cruise with cash with changes and cancellations. If you are open to renting you could even try to list points yourself and get $12 or maybe even $13 for an advance 11-month BLT reservation making your cruise "free" (or no cash out of your pocket).
You will have to see which stateroom/cruise works best for your situation, but I just wanted to give you some food for thought