Comment by jyriand

I found it useful when writing a thesis. It gave me a way to research many ideas, not directly connected to the main topic, but still interesting in my mind at least. I really enjoyed this unstructured approach. I didn't have to worry that I will get stuck, because I always had a way back to the main topic.

So, I think you need some kind of a goal, a bigger project, for Zettelkasten to become useful.