Not sure about the Madurai, But used at Delhi and Ahmedabad. It was pretty simple as the Airport Lounge.
Swipe the card/show the QR generated on the Dreamfolks. Sometimes they do ask for the ticket sometime not so depends on the staff and location.
Food is OK OK. Same as what we get inside the train. But again depends on the location.
I used idfc wealth at Chennai lounge. Swipe the card at the reception area share your ID proof and PNR number with them. Food is ok ok
As such, I would advise against utilizing the lounge access benefit in Varanasi. In contrast, the lounge facilities in Delhi are superior in every aspect and offer a more professional and comfortable environment.
I have used irctc lounge with ICICI mmt and coral credit card at new Delhi railway station.it was a nice experience away from crowded waiting area with good food.