It is mostly performance-related. For quite some time there have been people informing us that their devices could not run the game properly. So we hope that having a more barebone engine with control over what is loaded will help these people enjoy the game as well :)
And in the future, it will allow us to offer high quality minigames, as well as develop higher quality games in the long run. I’ve had my eye on a Peggle-Pachinko style minigame for a while, but don’t tell anyone I told you that ;P