Simply put – your website needs a sitemap in order to be found in SERPs. An XML sitemap helps search engines like Google and Bing easily understand your website’s structure while being crawled. And if your website has a complicated structure, or your website is new or has dynamic pages, a sitemap will greatly improve your ranking. Not only that, you will have a list of all URLs from your website and you get crawl priority. While you are not penalized for not having an XML sitemap, it is an essential aspect of SEO.