He says the reason people code client-side navigations is to load pages more quickly. That's not the reason. Client-side navigation evolved from single page app

He says the reason people code client-side navigations is to load pages more quickly. That's not the reason. Client-side navigation evolved from single page apps, where we use javascript to create dynamic content on the fly, for example a chat application. Now that you're a stateful single page app, we need to rebuild page navigation if our single-page-app has more than one "page". I understand that projects like Gatsby have used this technique for performance, but I see no reason that today's performance optimizations will be valid tomorrow. Page load performance is not the need driving this pattern generally.