Definitely not good to not receive proper visibility readings. However, the pilots should descend until decision altitude and if runway is NOT in sight they should abort the landing.
I fear that pilots flying modern planes (and the ATR is quite modern) are losing basic flying skills.
The Air France junior pilot completely mishandled what should have been a relatively minor event of the pitot tubes freezing up. And his superiors were of no timely help as they did not realize what was happening in time either. Airbus planes seem to be able to be hard to read at critical moments unless one is completely up to speed and ahead of what the aircraft is doing.
The Asiana crew were unable to visually land at SFO and crashed in good weather in daylight. They thought their 777 had auto throttle on and would not go below stalling speed, it seems.
There has been other crashes worldwide when crews went below minium altitude without seeing the runway and crashed.
That is why the final decision to land or not rests with the Captain. IF you can’t see the runway by decision altitude you are supposed to go around , make another attempt or head for alternate airports.
The SQ crash in TPE. The crew blamed “confusing runway lights” when they turned too early and took off on the wrong runway, thinking they were on the active runway. The airport could have some blame in using part of that closed runway as a taxiway. They should have closed it off entirely. However, the crew is mostly to blame for losing situational awareness and not confirming that they were in fact on the correct runway. They should have called for a follow me truck in the low visibility conditions at the time.
TPE airport also had no ground radar showing aircraft positions. So all in all, it was an accident waiting to happen on dark and stormy night. And it did happen.
Pilots were mostly to blame on that one, but there were extenuating circumstances that made the holes line up in the swiss cheese.
I hate flying as there are so many things that can go wrong. Luckily by far most of the time things go ok. We have tens of thousands of flights worldwide daily and only a handful of crashes a year.