well, perhaps a better understanding of RVR concept might bring some clarity into the pilots assessment. Let's start with definitions:
ICAO definition:
Runway Visual Range (RVR) — The range over which the pilot of an aircraft on the centerline of a runway can see the runway surface markings or the lights delineating the runway or identifying its centerline.
FAA definition:
Runway Visual Range (RVR) — An instrumentally derived value, based on standard calibrations, that represents the horizontal distance a pilot will see down the runway from the approach end; it is based on the sighting of either high intensity runway lights or on the visual contrast of other targets whichever yields the greater visual range. RVR, in contrast to prevailing or runway visibility, is based on what a pilot in a moving aircraft should see looking down the runway. RVR is horizontal visual range, not slant visual range. It is based on the measurement of a transmissometer made near the touchdown point of the instrument runway and is reported in hundreds of feet. RVR is used in lieu of RVV and/or prevailing visibility in determining minimums for a particular runway.
1.
Touchdown RVR — The RVR visibility readout values obtained from RVR equipment serving the runway touchdown zone.
2.
Mid-RVR — The RVR readout values obtained from RVR equipment located midfield of the runway.
3.
Rollout RVR — The RVR readout values obtained from RVR equipment located nearest the rollout end of the runway.
So far so good, what does it mean in practical terms? Well, nothing else but RVR can be assessed by a observer in the EU OPS land at least. The logical question is if a human observer can assess RVR why can't a pilot do so?
Well, please don't tell me coz we're superlative beings.