It stops at Borivali which is an extension of Mumbai , Vapi first city of Gujarat state (could have been ignored as Shatabdi is serving the same) , Surat (Diamond city , business hub of Gujarat with a population of well above 50 lacs , Vadodra ( again historical and third largest city of Gujarat with a population of above 30 lacs.)... ST , BR will remain the bare minimum stops for fastest bullet train between Mumbai and Ahmedabad as well. These cities provide essential traffic and can not be ignored. For context here , compare them with Bhubhaneswar and Cuttack which have a joint population less than 20 lacs. I think IR is worried about the occupancy of this train , they have a bad experience with Shatabdi on this route ... hence this "Local" offer !