The H1 tag has long been an example of an influential ranking factor and important signal to search engines as to what a page of content is about. The proportion of the H1’s influence on rankings compared to the overall picture has diminished over time, but is still considered an important ranking factor to many of the top minds in the SEO industry.
Title tags are often used on search engine results pages (SERPs) to display preview snippets for a given page, and are important both for SEO and social sharing. The title element of a web page is meant to be an accurate and concise description of a page's content.