Load and unload cargo ships more efficiently than with cranes. The time it takes to unload a cargo ship could take up to 30 days utilizing cranes and cranes are limited to being close to the shore. Every minute the ship is sitting outside of the pier not being unloaded or loaded money is lost. What if there was a way to reach cargo ships while they are near land but not necessarily docked in the pier.
The production of the gas powered cargo drones would have to be under a price point that would be less than or equal to operating and maintaining the cranes. Alternately, if there could be a premium cost for convenience in comparison to the cranes.