This article would benefit from an example page to show how these "feel".

Here are a series of demos. They work in Chrome or Safari.

https://view-transitions.chrome.dev/

Here's an older, more designed demo that only works in Chrome.

https://live-transitions.pages.dev

Run this snippet from TFA in the console on GitHub:

  document.startViewTransition(() => {
    document.documentElement.dataset.colorMode = 'dark' // 'light'
  });