You're not really shipping water, you're shipping plastic bottles with marketing labels. Once you think of it like that it makes more sense. Anyone that is buying Fiji water could already have a reusable bottle and drink from the tap.
No, it doesn't mean it's worth shipping water from an island across the ocean. In any case, my favorite water of all time is "El dorado springs", which happens to be sourced very close to me here in boulder, co.
The value is for the label, but the logistics are still shipping the weight of a ton of water