They are Just Promoting the Double Decker trains because they are running in Great Loss, Even 12931/32 Also.
Every trip more than 500 Seats go Empty.
And AFAIK Flying ranee was India's First DD train, Sinhagad Express, Brindavan Express, Coalfield Express etc trains were having DD Coaches much before Flying Ranee, Flying Ranee is Running on the DD Coaches of Sinhagad Express.