This was useful because I've been wondering about Anki for nonsense (e.g. math I don't already sort-of know, vocab for languages I don't know at all, etc.)
Re your second paragraph: Any updates to report?
It didn't last. I wasn't actively studying anything and my deck was too dominated with fluff that I stopped wanting to repeatedly see after a month or two of not actively adding any material.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.