Perhaps people are thinking about quality scores in the wrong way.
Experience shows that some media will not play at all in some DVD players, or it will start to play, and then pause and skip. This is despite the fact that it might have GREAT quality scans and zero PO Failures.
And the BenQ has definitely shown that its quality scan doesn't always catch an error that will cause a disc to coaster.
So, if we don't trust the quality scan, then why use it at all?
Because, although it WON'T show us if the disc was burned perfectly, it will allow us to visually eliminate an obvious BAD burn. Since there are a LOT of things that can cause a bad burn, it's good to be able to rule out at least some of the more obvious ones.