Probably nothing but he also is very critical of bicycle specific cartridge ebearings and advocates use of high end industrial bearings (nki skf) having found (according to him) that many bearings sold specifically for bike applications are watt sucking crap.
This is the way that con artists (big media, politicians) work. They pretend to have special knowledge of something you don't know about so they can create a false narrative, then tell you to do something you would not otherwise do.
Clue:
nothing can be perfectly round. If you look closely enough you will always find eccentricity.