Sitemaps can be very beneficial when it comes to generating SEO for your site and are also helpful for the user. 

The search optimization benefits of including a sitemap tend to be underestimated.  The purpose of a sitemap is to outline your site’s
content and show search engine spiders and visitors where to find information on your site.  It enables a birds-eye view of all of
the pages your site includes.

When you create a sitemap you give search engines an immediate alert that you have made changes to your site.  While this
does not guarantee that these search engines will immediately come to your site to view the new changes to your pages, it does ensure that it will
notice your site has changed as it crawls the web.  Sitemaps help diminish the reliance on external links that bring search engines
to your site.  

Another great advantage about including a sitemap is when you have created a new site, or added a large amount of new/updated pages; a sitemap can help
you organize all of this new content and is an efficient way to communicate with the search engines. This map for your site will guide the search
engine spiders to the links of all the major pages on your site. This is very good for SEO because the spider will know to index all of the pages.
If all your pages are indexed by the search engine database, it will make your site much more likely to come up in any search results done. If your
site does not consist of a sitemap creating one will benefit both your SEO results and your user audience, it’s a win win.