Why we use sitem.xml?

What is the use of sitemap.xml? If we not use this file then there is any problem in seo.:nono:

See if this helps:

see i am not too old in this field but i have gone through with few articles on this topic. i got that sitemap is important because whenever you search anything in search engine. spider or robot start searching for result when its reach at your site first thing they look out for robots.txt file to know which files are restricted or crawl and then sitemap to understand structure of site and reach on the right page. so if you have submit sitemap for your site then its better for crawler to crawl your website.

Sitemap.xml is useful for Google crawler or spider. sitemap is saw your whole website details and easy to understand for crawler of spider