Good or bad idea? I go with bad, I trust the men's game would never stoop as low as a points decider. Might be ok in tables for ODIs, even with a bonus point system, but not to decide the Ashes 
Although I do appreciate being the women's game the circumstances are somewhat different, still just doesn't sit right. They should just play an extra Test or two and maybe less often
BBC Sport - Women's Ashes 2013 decided by all three formats
The England and Wales Cricket Board and Cricket Australia have announced that August's Women's Ashes will be decided by playing all three formats.
The highest points total after one Test, three one-day internationals and three Twenty20s will win the Ashes.
Six points will be awarded for the winners of the Test in Wormsley from 11-14 August, with two points for each side in the event of a draw.
The limited-overs games which follow will see two points for a win
The final two T20 internationals, at Southampton and Chester-le-Street, will be played before the men's T20 internationals between England and Australia.
..............................
Head of England women's cricket, Clare Connor said: "We believe that this new multi-format series will gain significantly more profile and context than can be generated by playing a one-off Test match every couple of years."

Although I do appreciate being the women's game the circumstances are somewhat different, still just doesn't sit right. They should just play an extra Test or two and maybe less often
BBC Sport - Women's Ashes 2013 decided by all three formats
The England and Wales Cricket Board and Cricket Australia have announced that August's Women's Ashes will be decided by playing all three formats.
The highest points total after one Test, three one-day internationals and three Twenty20s will win the Ashes.
Six points will be awarded for the winners of the Test in Wormsley from 11-14 August, with two points for each side in the event of a draw.
The limited-overs games which follow will see two points for a win
The final two T20 internationals, at Southampton and Chester-le-Street, will be played before the men's T20 internationals between England and Australia.
..............................
Head of England women's cricket, Clare Connor said: "We believe that this new multi-format series will gain significantly more profile and context than can be generated by playing a one-off Test match every couple of years."