"Admit" what? You are so determined to be right about this when you are so clearly wrong.
Taking your position to the extreme, one could argue bringing wine on board is also not "saving money" because you could limit yourself to only drinking the free champagne provided at art auctions, right?
As has been stated previously, you are only viewing this through your lens. The DBP absolutely IS A SAVINGS for me, and certainly for others. For still others, no--the DBP would not make financial sense.
The plainest language example possible:
I do not drink wine (or at lest, very rarely)
I do not want to be subject to the "for in-stateroom consumption only" limitation on liquor gift packages (a discussion on breaking the rules is for another time, but the rule exists)
Therefore, if I am going to drink on a cruise, my options are to
Buy a drink package, or
Pay per drink
Again, it isn't for everyone, but I am speaking objectively here, purely in the form of dollars out the door. There is a verifiable savings for some people, including myself. In that respect, on every cruise for which I have had the DBP, the DBP saved me money because the number of drinks I consumed would have cost more if I were to have purchased them on a per drink basis. Q.E.D.