alt Hacker Newsauthor here -- agreed on all fronts. Mentioned this in the other comment but I approached the topic from a relatively narrow perspective (I was working on a specific project at the time)
I think it's worth including these things in a future update to the post, but I didn't have the time / need to explore it back then.
In the meantime, I'd point to the following post on Unicode that remains very nice to read >20 years later: https://www.joelonsoftware.com/2003/10/08/the-absolute-minim...
Sure, not all posts want to be the end-all of the topic. :-)
And yes, the Joel post is a good introduction, if a bit old by now. Notably, of course, it doesn't say anything about _processing_ Unicode text. (E.g., don't sort by code point, don't break in the middle of a grapheme cluster, etc. etc.) But I believe that this is outside the scope of his intention.