- Speed
- Static pages. No database query, no plugin chain, no theme to boot before the first paint. The three readings above are what that costs a visitor, and Google publishes the threshold each one is graded against.
- Structure
- Titles, headings and schema are written into the HTML at build time, not added afterwards by a plugin that can lapse at renewal. What a crawler reads is what you shipped.
- Images
- Compressed and sized during the build, in the formats a browser prefers. On most sites the largest thing on the page is a photo nobody resized, and it is the reading that drags the rest down.
- Clarity
- A ranking wins the click. The page decides whether the click becomes a phone call, so what the site says and where the number sits are part of the build rather than something you fill in after launch.