The risk
Ok, so it's all about the amount of risk you are willing to take. And what the rules are saying.
And the commercial airlines are taking that risk when flying 737 in 0 visibility. Because it haves 2 engines (2 chances), and you are more protected in that sort of airplane than in a light aircraft.
But if a 737 would get a double engine malfunction in 0 visibility it is almost certain that it will crash?
Have I understanded this correctly?