Weight won't matter much (you typically only accelerate it once, and the additional drag is small), it is just that the surface area is so small relative to what's needed that it just doesn't move the needle.
> It's made out of aluminum instead of steel. The resulting weight savings make it a bit more efficient. That's something this shipping yard specializes in.
According to that person, weight does indeed matter.
If you were optimising for mass rather than ease of maintenance you'd probably put them on (despite the relative lack of surface area meaning you still needed to recharge at each end)
There's also the matter of windage and what impacts that might have on the ship.
To say nothing of the capacity factor and reliability of electronics in a marine environment.