What CSV is
CSV is a text file where each line is a row and commas separate the fields. There is no type system, no formatting and no second sheet. Every value is text until something downstream decides otherwise.
Almost every database, analytics tool and spreadsheet can read and write it, which is why exports default to it.
What AsciiDoc is
AsciiDoc tables are delimited by |=== and take a cols attribute describing the columns.
Antora documentation sites, and technical writing teams that outgrew Markdown.
What changes when you convert CSV to AsciiDoc
Reading CSV means deciding three things the file does not state: which character separates fields, how quotes work, and what encoding the bytes are in. Tablizer sniffs the delimiter from the first few lines, handles quoted fields containing commas and newlines, and reads the file as UTF-8.
The header option is set so the first row renders as a header row rather than data.
What carries over from CSV to AsciiDoc
AsciiDoc can express everything CSV holds about a table, so this conversion is about shape rather than loss.
AsciiDoc marks its header cells differently from its data cells, so the first row is written with that marker.
The identifier 007 comes out of the AsciiDoc as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.
The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a AsciiDoc file goes wrong.
The quotes around Jonah "Jo" Pryce are left as a plain quote character in the AsciiDoc.