I don't think one should suggest Zettelkasten to anyone who is looking for a simple to-do list or note taking implementation. Regular notes are perfectly fine if one wants to take regular notes.

Luhman's zettels weren't random thoughts or casual ideas that popped into his head during a stroll with the dog., but rather full, jargon-laden sentences that were close to publication-ready in quality, sometimes highly abstract in nature. He would take a couple dozen related zettels, arrange them on a table in sequence, rearrange them and eventually have a rough outline for an article or the chapter of a book.

Here's a random zettel from Luhmann's archive, translated by deepl.com. This is 1 out of 90,000 total:

1.6c1 "About an activity, at one time, central and centralization." -- In some ways comparable to the view of Mary Parker Follett, Dynamic Administration, p. 183ff., e.g. p. 195: "Unity is always a process, not a product." -- But she confuses unity and unifying, and says below quite correctly (p. 195): "Business unifying must be understood as a process, not as a product." -- Except, of course, that the word unity does not mean process, this dynamic view is that the process can be described as valuable and characterizes the organizational view, from the finished fake unit to the unification unit process.

Source: https://niklas-luhmann-archiv.de/bestand/zettelkasten/zettel...