I'm not sure I buy the "React is replacement, not augmentation" argument. At the end of the day/render, React still renders HTML elements... with javascript event handlers. Wrapping an ' ' in a React component doesn't mean I've taken away any functionality of 'img'. I just add to it -- augmentation. Maybe the author has worked in different React codebases than I have, but in my experience, we use built-in browser fun…
React (rendering in the browser, not server side): Page Load -> Component Load
vs.
Web Component Page Load -> Default Render -> Component Load
So if someone has JS disabled they would still see SOMETHING for the web component vs. nothing in React. And with JS they could get to some further render state.