BIDR-GR definitely needs long distance trains, as it is a reasonably long branch line and also provides connectivity options that weren't possible before.
Until the Raichur-Ginigera line is completed, RC-Gadwal line will be better served by frequent DEMU/passenger services. It is just a 50km branch line and end-to-end travel will hardly take 1 hour, with the routes at both ends also connecting to Hyderabad and Guntakal. In such a scenario, instead of trying for a new long distance train just for this 50km section, since both ends of the section are already on major long distance routes, frequent end-to-end passenger services will let people catch long distance trains at Raichur or Gadwal.