On-page optimization helps search engines quickly understand the overall structure of your content and what it is about. It makes it easy for search engines to interpret the content against user searches swiftly. Search engines display the page to users in SERPs if it identifies the page content is relevant to the search query and can answer the user query. It also makes the user wait for a long-time or go through other similar pages on your site, improving the site interaction rate and reducing the bounce rate.