Cargo ships with marine diesel engines that are aided with a few sails is not, going back to sail.

The noise will still be there.

They mention a 30% fuel saving. This is not about reducing sea trade it is about cost savings, making sea trade cheaper and likely leading to more ships, not less on the oceans,

Even it it lead to 30% less ships, this would only take the world back to about 2010 as sea trade had grown by more than 30% since then.