Really great in-depth article! At this point in my life I feel like there's such a large amount of content for "beginners" written by people who have only been coding for five years, and a huge dearth of "intermediate" content for people who are adults, and who do know how to code, but who would benefit from being walked through the deeper parts of the language, and this article really fits into that sweet spot for me.
This functionality in Erlang is something I miss in most other languages, and I was quite displeased when I discovered Python 3 abandoned tuple destructuring in function invocations.
Interesting use of <details> to show the results of a computation. I missed the explanation in the beginning that said the results were precomputed. I thought clicking it was running. Format-wise since it's not actually running when clicked, I'm not sure hiding the result behind <details> is much clearer than just including the result as displayed by the REPL in the same snippet.