I'm surprised there's such a cable in the first place, it seems it would be easier to go on land through Denmark and Sweden. Is it for some reason easier to have an undersea cable than a land one?
It's much easier to lay a cable on the bottom of the sea. There's nothing interfering there, you don't have to dig, you don't have to put up poles. If you give it some thought, you'll realize how much easier it is to have an undersea cable.