In the TV Series "The Expanse", in the first episode, about 12 minutes in, we see the ice trawler Canterbury collecting large pieces of ice as cargo, to ship them to Ceres.

The collecting work is done by drones and cranes.

Why do they even load the ice into a ship, instead of shipping it right away with the use of the drones all the way to Ceres?

I guess this would be be much more cost effective, left alone less dangerous.