in my view is to avoid the trouble of resetting the calendar after the watch ran out of power. So they need a long power reserve in a manual watch to avoid this. I don't think it is accuracy driven, although this system allows for a 5 Hz "active" balance wheel that should run very accurately.
You bring up some very good questions! I love your idea of having two balance wheels that run simultaneously and average out the accuracy. After the Tourbillon and the Resonance, this could be a huge innovation!
Thanks a lot for your thoughts and comments, Patrick, I appreciate it a lot.
Daniel