I can bet this VB was extended to Rewa SOLELY because of POLITICAL REASONS. The extension was obvious, and essential as it was directly competing with Janshatabdi, and people are bound to prefer 12061/2 as VB saved nothing more than an hour.
But, Rewa came into the picture because of the local MLA. He used to talk about and try to appease the local populace when the VB was not even inaugurated from JBP. Hence, just so that the citizenry of Rewa get to experience this contemporary railway technology, the MLA and current Dy. CM of MP asked for an extension to Rewa to save upon his votebank.