Butterick introduced me to Bitstream Charter for which I'm very greatful. However, I would very strongly urge people to disregard his recommendations for representing hyperlinks.
Instead of just underlining hyperlinks, he has this demented nonsense:
> Cross-references, denoted with small caps, are clickable.
> Links to outside material are denoted with a red circle, like so.
Hyperlinks are almost universally distinguished by underlining them. There is no rational reason to invent a new design language and expect people to learn it. And for what benefit? The seemingly random capitalisation of words and weird circles in the middle of the text makes it much more jarring than simple underlining.
Smallcaps hyperlinks is even worse than it might initially sound: many ESL speakers have difficulty with text written in all-caps, and it totally makes sense why, if you think about it.
...why? I'm thinking about it and don't have the slightest idea. And it's not a difficulty I ever came across with my students when I taught ESL.
All-uppercase distorts the shapes, making them unfamiliar to ESL readers who have less practice. You must know that famous meme about how you can read English perfectly fine if the letters (besides first and last) of each word are scrambled: "Aoccdrnig to rscheearch at Cmabrigde Uinervtisy..."
Granted, I'm not an expert in this area. I'm actually just relaying what an ESL ex of mine told me. She hated whenever she had to read things like "Calvin and Hobbes" which use all-caps, for this exact reason. Come to think of it, she was Japanese, I wonder if it has to do with growing up with a logographic writing system.
Uppercase doesn't distort shapes, they're just the uppercase shapes. Reading in all-uppercase is a basic skill that you quickly learn, since it's extremely common in signs, titles, etc.
I can understand that learning separate letters for lowercase and uppercase is something that students coming from other writing systems have to learn, the same way I had to learn both uppercase and lowercase in Greek.
But it's just a year-one skill you have to learn. You learn it, fairly quickly, and then you're fine. It's not a reason to avoid using small caps. Generally speaking, by the time your English skills are good enough to read an average paragraph, text in all-uppercase has not been a problem for you for a long time. Vocabulary is the thing that takes a long time to learn, not recognizing words in uppercase.
So while I don't doubt that your ex was telling the truth about Calvin and Hobbes, I think that was just a personal annoyance of hers. It's not a widespread problem. But everybody winds up having their own idiosyncratic annoyances with foreign languages.