Almost 10-15 years back, remember for almost one year DHN-Allp used to skip Chennai and go via Perambur. It was SR only which reversed the decision as there was lot of demand from passengers.In case of these set of trains, I guess their arrival/dep times from Chennai ( both sides) is at a time when there is relatively lesser congestion (arrival/dep around midnight). Maybe that could be one reason why SR seems to have not much objection for these set of trains.
The real benefit for passengers will only be when skipping these major stations results in lesser travel time