Does the Sitemap Help in SEO?
Googlebot uses the sitemap files (page sitemap and sitemap.xml) to discover content. The pages discovered go into the ranking algorithm and then got their positions in the search results. It is fundamental to offer at least the XML file as a map to content discovery. Google Search Console has a tab where you can submit it, and Googlebot will prioritize the crawling of pages. In the sitemap file, you get to include only those pages you want to show up in search, and you may add more information like alternate URLs for the languages present on site.
When the Googlebot crawls a list of prioritized URLs on a site (because it runs on limited resources), it may encounter errors. Sometimes, there are also old URLs in the Sitemap that don't exist anymore. Bad navigation, lack of interlinking, server errors, sitemap false page reporting, all those things may confuse Googlebot and assign a low crawling priority to the site. There are online tools that help with each error from lost links, missing pages, excessive redirect chains or loops, and of course, Google offers the Search Console with some reports that help webmasters identify the mishaps.