This approach is not unique to Svelte(Kit), and not particularly efficient. You serialize the entire app state at once, and still have to send the complete appl

This approach is not unique to Svelte(Kit), and not particularly efficient. You serialize the entire app state at once, and still have to send the complete application/component code down the wire and execute. It’s how this has been done for the past decade. The main advantage Svelte has is that it doesn’t need a “reconciliation” step, since it doesn’t use a virtual DOM, so this whole dance takes a lot less CPU time. The ideal scenario is that you only serialize state, download and execute code for the parts of the app that are actually interactive. This is now called “partial hydration”.