It would be weird having a double of yourself. Who is the real one and who is the double? But it could be convenient, like what Natsumi did. She let the double{?} do the house chores and help the other girls study while the other Natsumi practiced for her tennis match.
And when they return to being one, both memories and experiences are shared into that one.
I wish there two Saki though~
Open Your Mind 