Probably something to do with parties? Or maybe you’ll be able to assign players in-game as temporary co-captains who can manage your ship and cannons, and sail it freely without getting into trouble?
Could also be something completely cosmetic as well.
It’s just wilderness islands to fill out the ocean… There’s no reason for them to be big, we all know that overextended filler of land is not good for gameplay, it was a mistake WoM did.