Google is a fully automated search engine that uses web crawlers to explore the web constantly. Technically, Googlebot crawls everything existing on your website. It determines if the content of each page is relevant enough for each query. If you want to learn more on . Googlebot access your website’s CSS, JavaScript, and image files, too. It analyzes the content of each page and stores the information it gathers. Thus, if your website is not optimized properly for search engines, it will immediately aggravate Google algorithm’s ability to render and index your content.  As a result, this will lead to low SEO rankings on Google. But if you have optimized your website and constantly take care of it, then you have nothing to worry.