Taking this topic to something specific if you can answer this . For planning purposes when any of the destination / alternates has a precision approach then only the stated RVR is taken into consideration for planning purposes . But what about once you are flying ? You are inbound somewhere and you get constant reports that RVR for that ILS is above minima but ceiling is below minima (and it never gets better or is actually dropping). Do you go for that approach or not .
I am not sure what the answer is . In real life years ago we were trying an ILS . Everyone was going around and it’s seemed it was due to a very low cloud base . However the tower was only reporting the RVR which was above minima . Just like the others we reach minima and never saw and went around . The reason was the low ceiling which wasn’t stated by the tower .