[Qwertious]

The ballast is for cargo, which needs to be picked up and dropped off. Fuel is just a potential solution.

[Ajedi32]

Why condense water from fuel or the air then when you can just connect to the local municipal water system? You're already at port!

[Qwertious]

Not necessarily - the great thing about airships is that they can go anywhere, and pick up cargo at places that aren't ports. You can go pick up logs from logging camps directly, for example.