Raiten Ka
Because they are tired from us complaining about the latest quest (which I think it's UNFAIR for us veterans). So they think they can do this since we're being "unfair" to them.
Erm, I doubt their reasoning is as passive aggressive as that. They likely just want to give additional incentive to get new players to sign up.
Though I personally think creating such incentives, while snubbing existing and loyal users is especially unfair, especially in a game where we're encouraged to "catch them all".