The idea of people using virtual currency to teach people how to effectively manage money is interesting. However if you look at the implantations that are out there right now, most if not all of places where virtual currency is being used, they are used either to help drive traffic, increase user loyalty or increase advertising dollars for the social networks. In exchange users redeem their currency for virtual gifts or higher status.

I am not sure they encourage people to save since the only reason to save is to spend; there is no way to invest virtual currency; though that would be a very interesting model to adopt. Virtual currencies are quickly becoming analogous to frequent flier miles offered by airlines.