What a great article! I heartily agree with all points, although I haven’t used Storybook and need to work out how to make my larger components more testable.

I especially appreciate your caveat about styled components. I feel like CSS is too often the neglected stepchild of the browser, and I frequently see people simply going for CSS-in-JS just because they’re unfamiliar with CSS and how to make it modular. CSS-in-JS is a tool, but knowing why to use it, beyond simply “I don’t want to CSS,” is pretty important.