As it is a Rajdhani only one station in the region should be given halt. Purulia is well connected with Raghunathpur, Adra and nearby areas both by road and rail compared to Anara so it can be given halt. However, thats a feasibility point which railway thinks to ignore may be cause of Anara being a track changing point for this train.
When ASN is near with options like HWH and SDAH RAJ, Purulia people can continue to avail them over BBS Raj.