Because Temari's techniques revolve around cutting or slicing. This will be ineffective against Konan since she can just join back up.How would turning into pieces of paper help her in combating Temari's Wind techniques that are powerful enough to cut down a forest?
If Temari uses a stronger wind technique it would just leave her with less chakra since Konan can just split and join herself up again.
It doesn't matter if Temari uses a strong or weak wind jutsu the result will still be the same.