SSL certificates are used to encrypt the transmitted information to secure identities and financial information over the web. At this time, all websites should have an SSL certificate for data integrity, encryption, and authentication, whether it collects private information or not.
Google also loves security and would like to establish secure environment over the internet, therefore Google starts giving ranking advantage in search engine to secure HTTPS websites.
However, most important thing – user trust. When users search for the product on search engine and see your website “HTTPS” then users already known that the website is secured and there will be more chances to visit your website and convert visitors into the buyers.