Re: Why not Atom?
Because (and this is a guess), W10 doesn't have the capacity to make phone calls and WM10 won't run W32 applications.
If the Universal Platform thing takes off, however, you won't need W32 applications. And this thing (and others like it) is the best possible reason for the Universal Platform to become popular because MDM can lock down a smartphone like nothing on earth with basically zero administration (cost saving), phones are comparatively dirt cheap (cost saving) and there are a gazillion office drones out there who only use MS Office every day (which is already a Universal app) so... big fat cost saving.
Short version - it isn't aimed at us. It's aimed at the kind of corporate that orders 500 shitty HP desktop boxes at a time.