Kyle Mathews discusses the importance of web performance and how the framework Gatsby excels in creating fast-loading websites. He highlights the significance of metrics like Speed Index and Time to Interactive (TTI) in measuring site performance, using tests on platforms like webpagetest.org to showcase Gatsby's superior performance compared to other well-known websites. Mathews explains that Gatsby's speed stems from its ability to automatically optimize the site's configuration and prefetch resources, allowing developers to focus on content and design rather than performance intricacies. He suggests deferring non-essential JavaScript to improve loading times and emphasizes Gatsby's role in providing a modern development environment that handles performance optimization. Mathews encourages developers to try Gatsby, especially those interested in React or seeking to enhance their site's performance, and invites performance-focused engineers to contribute to Gatsby's continued improvement.