So this expert is just some flake who runs a recording studio in Europe who's claim to fame is a plug in for electronic music production that measures the dynamic range of music a few years ago. His meter is totally obsolete now, superseded by LUFs meters.
Now he is schilling for what amounts to audio magic beans. At one point in the video he intones that you should not try to measure with objective tools the output and instead just judge it with your ears. That is a huge red flag, no real engineer would ever say such foolishness.
He also lets it slip that if you should never measure the frequency levels or bands or curves or dynamic range of the output of this device and compare those results with the original unprocessed sound. He also says if you do you will see no difference, none of that is changed.
This is kind of like the flat earth of music.
"Meet the new Boss, same as the old Boss." - The Who.