Voted option 1. For me, gameplay always trumps realism.
Besides, having it be instant doesn't take anything away from the game. If it breaks immersion for you, don't use it; all the previous options are still available.
That said, a delay wouldn't be terrible. All it requires is a bit of forethought. New cargo CG is golden and I don't have my cargo ship with me? Log in before dinner and start the transfer, by the time I play that night it will be done.