Not sure I understand right what this article is about. From my point of view, CSV is an easy way to export data from a system to allow an end user to import it

Not sure I understand right what this article is about. From my point of view, CSV is an easy way to export data from a system to allow an end user to import it in excel and work on this data. Apart if it's as easy with parquet to import in excel as with a CSV, I'm not sure this is not fixing a problem that doesn't exist. And making things more complicated. Outside of the context of end user, I don't see any advantages in this compared to xml or json export.