I will say that Donkey Kong, Pac-Man and Asteroids were all originally arcade games where you DID spend coins to beat your high score. That was their primary means of making money back in those days.
(And I disagree that the coin system in RBB is badly implemented so...)
The 2.6 million users that play Bejeweled Blitz each day beg to differ.
Neither is using coins unless you're playing for score/leaderboard position. In which case Achievements are the same because you don't have to complete all of them, but you get achievement points for doing so. And that can be a significant driver in getting people to play differently.
I would bet that you're going to see more of this in the future. This is not the last time nor the first time this has been done. (Pretty sure you've been able to get in-game rewards for playing FB versions of console games from UbiSoft before, at least. Doesn't Halo Waypoint have something similar-ish?) It's just a little more front and center here than previously.