In 2018, Google announced that PageSpeed was now a factor for how web pages would rank. Think about it, no one wants to click a link from Google and have it taking forever to load. Google realizes this, and so in recent years it has become a much larger factor in their algorithm.
In May 2021, the Google Page Experience update adds even more to this, as Google has now done more to help developers know where to focus on when it comes to page speed, as it affects user experience.
This includes the metrics from Google’s Core Web Vitals, which they say includes:
Loading, in this context, measures perceived load speed. That’s the point in the page load timeline when the main content is likely to have loaded.
Interactivity is the time from when a user first interacts with a page – a click or a tap, for example — to the time when the browser begins processing that interaction.
Visual stability has to do with preventing annoying and unexpected movement of page content.