docs: tweak intro perf section

Author: yyx990803

docs/guide/what-is-vitepress.md

@@ -34,11 +34,11 @@ VitePress aims to provide a great Developer Experience (DX) when working with Ma
 
 ## Performance
 
-Unlike many traditional SSGs, a website generated by VitePress is in fact a [Single Page Application](https://en.wikipedia.org/wiki/Single-page_application) (SPA).
+Unlike many traditional SSGs where each navigation results in a full page reload, a website generated by VitePress serves static HTML on the initial visit, but becomes a [Single Page Application](https://en.wikipedia.org/wiki/Single-page_application) (SPA) for subsequent navigation within the site. This model, in our opinion, provides an optimal balance for performance:
 
 - **Fast Initial Load**
 
-  The initial visit to any page will be served the static, pre-rendered HTML for blazing fast loading speed and optimal SEO. The page then loads a JavaScript bundle that turns the page into a Vue SPA ("hydration"). The hydration process is extremely fast: on [PageSpeed Insights](https://pagespeed.web.dev/report?url=https%3A%2F%2Fvitepress.dev%2F), typical VitePress sites achieve near-perfect performance scores even on low-end mobile devices with a slow network.
+  The initial visit to any page will be served the static, pre-rendered HTML for fast loading speed and optimal SEO. The page then loads a JavaScript bundle that turns the page into a Vue SPA ("hydration"). Contrary to common assumptions of SPA hydration being slow, this process is actually extremely fast thanks to Vue 3's raw performance and compiler optimizations. On [PageSpeed Insights](https://pagespeed.web.dev/report?url=https%3A%2F%2Fvitepress.dev%2F), typical VitePress sites achieve near-perfect performance scores even on low-end mobile devices with a slow network.
 
 - **Fast Post-load Navigation**