Windows shouldn't have let this happen, they should've just added a few budget phones to their portfolio and that's it, not do this hybyrid that will only increment the popularity of android.
Probably just an experiment on Nokia's part or perhaps it is just a handshake deal to try to draw phone manufacturers into making Windows phones.
There's some sort of strategy there be it wise or not.
The dualSIM feature will very attractive to a lot of border crossing travelers tho.