There are several reasons why search engine submissions support search engine optimization (SEO) efforts.
1) The sooner the better.
The quicker search engines discover a website or a new piece of content, the faster they can start ranking it in their search results (if they choose to).
Search engine bots will inevitably find your website, but why wait to get discovered when you can begin communicating with Google now?
2) Tell Google about your site.
Scanning a website only provides certain bits of information to Google so search engine submissions offer an opportunity to tell Google important things about your site, such as pages that are most important based on site structure and hierarchy in a sitemap.
3) Make your website better.
When Google scans your website, they will let you know if they encounter any errors or site issues.
These insights provide a clear roadmap to constantly improve your website’s user experience and functionality – particularly on mobile devices.