We all want our websites to be secure and ranking higher than our competitors through organic SEO, so just having an 'S' can make all the difference.
If two competitors website has otherwise same web pages, search engines prefer a domain name with HTTPS (Hypertext Transfer Protocol Secure) sites, pushing the secure domain to take the lead, so why not add an s.
Yes, we need to make our websites secure, primarily if we sell online, though It encrypts all communication, including URL's, protecting things like browsing history not just credit card numbers.
Your website designer, IT department or hosting company can help install these for you. You have to buy an SSL certificate, and these start at around £50, including installation.