User blog comment:IamJakuhoRaikoben/Chapter 513: Flower Circle, Review./@comment-7418318-20161205162009/@comment-7418318-20161205164400

Yeah, but here it is a very relevant connection, not an inconsequential one.

That Anna helped Igneel make the scarf is just trivia, but Erza potentially being Acnologia's daughter in law or hell maybe even actual daughter is sure as hell highly relevent for the end-game. And even if Irene turns out to be unrelated to Acnologia and just having similar titles, still being Irene's daughter or creation is also a very relevant connection completely unlike the scarf-knitting.

At least with Gray and Silver it served the purpose of setting up the Natsu and Gray rivalry... dubious as that "benefit" might be, but is there any purpose at all for Irene to be related to Erza? Because I sure can't see it yet.

If Mashima finds a way to make it actually relevant, I'll be a hell of a (positive) surprise, but as I said I just can't see any way for that to happen.