You have answered your own question. It helps to provide information to google about the new pages or the relevant pages of your website to get crawled. This will help to get your webpages indexed with google.
XML site map definitely helps to crawling your website. XML is known as search engine friendly language and with the use of XML sitemap Web crawlers easily access both deep and high level links in your site.
When you create a new website you must include the following point in your XML sitemap.
1) Web page links
2) Last modified date
3) Frequency of Crawling
4) Update the frequency of Crawling
5) Web page Priority