Here's what he had to say about it recently (edited for brevity and forum rules)
I am looking at several different watches in the $8-$10K retail
range. One ... model has the features that I want. Yet for virtually
the same price, but with less features, they have a certified
chronometer." Is there real value in a certified chronometer, or is it
just a cash grab?
Unless you’re planning a solo
circumnavigation of the globe without the use of GPS, chronometer
certification shouldn’t be reason to part with more money.
Modern
engineering and manufacturing means that it isn’t as hard as it used to
be for a watch to keep time to within minus-four to plus-six seconds per
day. Even a well-adjusted low-end ETA movement can achieve this, and,
frankly, I think you should expect this sort of performance out of any
watch you buy these days, especially one in the price range you’re
looking in, whether certified or not.