Take a look at how you want to eat while there. For 3 nights, if you're looking to dine at least at 3 TS restaurants and 3 CS restaurants, then it most likely will be a savings.
Since it's not front-loaded like ticket prices, the savings would be roughly the same (percentage-wise) across any length of stay.
If, however, you plan to share most meals, or only want a single TS meal, then chances are it won't be a value. It's all a matter of how you plan to eat and only by utilizing what is offered will you be able to gain any savings.
Along the same vein, DxDDP can be a savings for a short trip as well, again, so long as you plan to utilize the offerings.