Aww, come now, am I the only one that actually likes the little sword?
I don't see the sword coming in to play at any time in the future, mainly because, aside from the fact it is the "sword of Blackbeard," there is nothing that special about it. Perhaps if there was a little unusable skill on it that said "Does critical damage to zombies!," then yes, I could see it coming in to play.
But other than that, this is most likely just a promotional tool for the upcoming movie, and perhaps a little hint for updates to come. (I can see an article saying "Blackbeard has come to the Caribbean in search of the Fountain of Youth!" right on the horizon.)