Please edit title bhai, even Sarv Dharam Sangam added back on LCN 690. Airtel is really good at negotiating deals, people used to say that Tata Sky hardly dropped channels but now airtel has much better track record than them.
No channel is really useless or extremely good, it all depends on one's preference. Religious channels may have minute audience as compared to major genres like entertainment or music or movies but they can't be termed unimportant just bcoz of this.
I for one watch most of the Hindi and English Channels across genres including regional news channels or religious ones or even DD Regional Channels and enjoy some of their content.