That maybe is a good idea for someone.
Not for me!
I don't like it, how will they be loaded on container terminals or any other?
What if they have to sail under some bridges?
I guess most companies will use "normal" ships for carrying cargo, you need an experienced crane men for loading this boys.
Maybe, this would be more useful if they would have retractable masts like funnels of the oasis of the seas.
So when they come to port, they will be able to retract them.
Concept can be made on retractable fishing rod?
Those were my first thoughts.