Does it make any difference to add .html after the URL from SEO point of view?

The answer is NO! It doesn't make any difference as long as the URLs are meaningful and readable by search engines. Search engines recommend static HTML files just for the sake of easy accessibility and readability. Search engines find it difficult to read long dynamic URLs though most of the search engine are capable enough to read the most of the complex URLs but still we should try to make this process easy for better crawling and indexing by keeping our URLs static. Even if you manage a CMS driven website where all the pages are dynamic  or virtual you can make rewirte them in static format.