Title Tag (also called as Page Title) is the first thing a web user sees after performing the search result. Title tag is also the first thing looked at by the search engine bot while crawling a web page.
While it is not a critical visual element, it is quite important as it gives the initial context of your page, thereby helping both the end user and the search bots. Therefore, write page title that is unique, action oriented and highly contextual to the search query so that it can generate a click.