XML Sitemap of a website will be created and submitted to webmaster's console in order to ping the search engines crawler to index the inner-pages of the website.
But, apart from XML Sitemap; HTML Sitemap will be integrated into a website by default.
So, what is the benefit of a HTML Sitemap? Is it necessary to integrate a HTML Sitemap into the website? If yes, what are its uses?
Having a Google Sitemap for a site is a must if Search Engine Optimization is your priorities. Sitemap account tells us is when did the Google bots visited our sites.The latest addition to Google Sitemap account is the Links Statistics. This set of data will show us how many incoming links do we have from both external and internal pages.
Sitemaps are often a great way to improve search engine visibility because it enables all pages to be found. With many websites, for example, the navigation is in flash or some other technology, such as AJAX, which makes it difficult or impossible to be crawled via search engines. Sitemaps correct this problem. Additionally, sitemaps are particularly useful for large websites, frequently updated websites, and websites full of archival content, whose pages are hard to reach via links.
1.) Even if you're using AJAX, if you're doing it right, your site should still be crawlable by bots.
2.) If you're doing your main navigation correctly, there is no need for a user html sitemap... if a user needs to reference an html sitemap to navigate your site, your navigation is broken (that includes indirect methods like site searches).
3.) You definitely should do an xml sitemap. When bots crawl your site they crawl at the hierarchy given, if certain pages are too deep in that hierarchy they may be missed due to bots limiting both the crawl time and depth. Providing a sitemap essentially gives the bot a flat view of every page of your site all in a single location, which means it can crawl those often missed but possibly useful pages.
Using sitemaps has many benefits, not only easier navigation and better visibility by search engines. Sitemaps offer the opportunity to inform search engines immediately about any changes on your site. Of course, you cannot expect that search engines will rush right away to index your changed pages but certainly the changes will be indexed faster, compared to when you don't have a sitemap.