Ask HN: Opinion on Inline Expandable Footnotes?

I am a writer who spends a lot of time balancing narrative with technical detail. I find this really challenging.

I just saw an interesting technique that could help: inline expandable text. This is used in this NY Times article below to present footnotes:

https://www.nytimes.com/interactive/2019/06/21/opinion/editorials/errol-morris-lobster-sviatoslav-richter.html

Has anyone seen this technique used before? Any comments on it?