most people wouldn't be that bothered about the hassle of plugging two cables in
Sorry, but I don't agree, Moto. Some of us are willing to pay more for the convenience of NOT having to connect the drive -- or not requiring the computer owner to do this.
Yes, I know the OP asked about hot swapping, and my comment was more about cold swapping. But I felt it was applicable to the question, since many people buy hot swapping equipment to actually cold swap.