Tell your fiancee that I think it is worth the cost, since it is basically a prepay thing.
The biggest draw for me, as a guy, is the preplanning ability! You will be able to get reservations in advance for Palo and get your dinning rotation early. This means you can choose which restaurant you want to skip for Palo and on what day. It won't be a surprise afterward.
Next best reason is the spa factor. You will have a spa treatment prepaid, thus no large bill at the end of the cruise! You know you'll get one anyway, so why not pay for it in advance and on your own terms. Plus, as with Palo, you can have the reservation set in advance, so you will not be hurrying as the cruise is about to start for it.
Finally, you get all the added stuff like the champaign breakfast and such. This makes you happy and that should make his cruise happy
Besides, I believe a honeymoon should be as all out as possible to avoid any regrets, since you only get one real honeymoon to start your life together.
Those are my thoughts. Good luck!!