We are happy to announce that Let's Encrypt SSL certificates are now built-in to every account for all of our hosting customers. Every account will be scanned regularly and given a Let's Encrypt certificate for free, if they do not already have one. cPanel will also replace expired certificates. There is no impact for sites that choose not to use HTTPS, as it can be simply ignored.
Although these certificates are valid, users are responsible for redirecting their traffic to HTTPS - and making sure their websites are SSL ready.