I'd bet more on this being because the original Scroll only works on accounts who don't have any expansion past BC, which is pretty unlikely at this point. Why would you "come back to see what's new" if you can't even get to the new content anymore?
I'm betting they're just changing what it does. I'm expecting to see them relaunching it with some promo item you get if you use the scroll and then restart your subscription. Or a bonus to the person who sent it. Probably a pet or a mount that's just a color-swap of a current one.