Two undersea cables in Baltic Sea disrupted

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?

You can see an undersea cable map here. I don't know about cables specifically but:

1. Anything sea based tends to be cheaper than land based, both in terms of sea transport and also lack of other interfering infrastructure, homes etc along the way

2. Shorter distance means lower latency

3. There surely is a land cable too. There's a lot of redunancy in the system

https://www.submarinecablemap.com/