What a coincidence. Just these days I was thinking about this. I have a physical zettelkasten, and lately I've been thinking that, for learning, maybe the method is not that useful, and it is only for research, writing and publishing. What do you think? Should I use to learn topics that I do not plan to be writing about (yet)? Or should I leave it aside for now, and use a Commonplace Book or a more BASB-like digital zettelkasten? Thing is, I really like the mobility of an index card (something that a notebook page doesn't have). But, in the other hand, you know that, in the commonplace tradition, the notebook was the weapon of choice. I am still confused if I should use my zettelkasten only for writing, or use what I have for learning too (falling a little in sink-cost fallacy)