The blog post by Paul Scanlon discusses optimizing JavaScript animations in Gatsby sites without affecting performance, particularly focusing on metrics such as Time To Interactive and Total Blocking Time. Using libraries like three.js and react-three-fiber can increase bundle sizes, which impacts these performance metrics. Scanlon suggests employing React's Code-Splitting, React.lazy, and Suspense to defer loading non-essential animations, which are considered incidental and not crucial to the site's content. He emphasizes the importance of not "lazy-loading" critical content and details conditions for further optimizing performance on small screens or when users have data-saving features enabled. The piece balances the need for creative web animations with maintaining a performant and user-friendly experience, advocating for a middle ground between innovation and efficiency.