Not everyone likes working with index card files. Some are definitely opposed to them, as I tried to show in Critique of Zettelkasten.
In a German review of Erwin Einzinger's recently published novel "Aus der Geschichte der Unterhaltungsmusik" (Residenz, 527 Seiten. 24,90 Euro), which is called Ein wüster Zettelkasten-Roman, there is the following accusation: the book is "a textual alluvium that knows no structure and no line. This 'story' is like the extract of a gargantuan and unordered heap of index cards or notes, compared with which Arno Schmidt's and Frederike Mayröcker's chaos of notes look like the carefully arranged contents of a small drawer in a night stand."1 It is a "wild index-card novel."
I have no interest in the book. I don't even know whether it was written, using the index-card method. The only thing that makes it (or the review) interesting to me is the claim that a product like this must be the result of using index cards in writing.
I don't think that there is any necessary connection between such a book and card files. In fact, I am doubtful that there is even so much as a strong correlation.
1 In German: "einem Text-Schwemmland, das keine Struktur kennt und keine Linie einhält. Diese "Geschichte" ist wie der Extrakt eines riesigen, ungeordneten Zettel/Notizen-Haufens, gegen den sich Arno Schmidts oder Friederike Mayröckers Notizen-Chaos ausnimmt wie sauber geschlichteter Inhalt eines Nachtkasten-Lädchens."