Cursed Sails region sails significance?

I've seen mixed opinions about the region based sails you get for following the Cursed Sails story. Some say they're needed and others say they're not. I know when I first jumped on I was able to go fight the skeleton ships right away. Some groups I join say "make sure you go change your sails". I guess my question is are they needed for whatever region you fight in or are they just for show?