Was there an ILS in Lucknow? Seems like it given the RVRs listed on AVherald. They were overhead with minimum fuel (1100kg), that was the point they should have done an autoland regardless, and if they get visual, take the autopilot out for a manual landing. If the RVR is 1m, the autoland system doesn't care. I appreciate that terrain (rather than ILS quality/lighting) might prohibit the autolanding on a technical basis, but a dodgy autoland is probably a lot more comfortable than actually running out of fuel whilst still in the air.
Also, someone correct me, but is a modern A320 with FLS capable of landing automatically from an NPA with a MAP over the threshold? This aircraft was an A320 neo so quite possibly technically equipped for that as an even laster last resort?
Scary stuff all the same, those lucky people!!