This is a good point - At the end I mention some built in advantages of global, externally defined CSS and I should add the point about caching to that list. I

This is a good point - At the end I mention some built in advantages of global, externally defined CSS and I should add the point about caching to that list. I also mention more powerful implementations of inline styles, though, like styled-components, which you can actually use to generate cachable stylesheets on the server while keeping all your CSS scoped inline. One thing I'll go back and reword in the article is this notion that inline == style attribute. I can see how this comes across, but I'm really talking about 'inline' the pattern more than a specific implementation. Using CSS-in-JS to add styles to a style attribute is one implementation, with, as you point out, some downsides - there are others that provide more features while keeping the component-centric model.