I always think it is worth it. Compared to drinking at home, it is expensive. Compared to buying by the drink on the ship, it is cheap. We drink a lot of bottled water, energy drinks , premium teas and coffees and mock tails and hate being limited. We always go with the refreshment package which includes everything nonalcoholic. I watch people drinking the free lemonade and iced tea and trying to stir them up and think how much I would hate that. Each to their own but if you you spend the money to cruise, you should enjoy it fully.
Just for info, I am very cheap ( frugal) but drink packages is not the place I skimp.