If we do have a comprehensive set of tests that give us confidence that each commit to the code repository is working as expected and if there is a repeatable and reliable Deployment process, there is no real reason for not taking that extra mile and automatically deploying each release to production.
You might choose not to do Continuous Deployment. Maybe your process requires us to cherry pick features. Maybe our marketing department does not want new features to be available before their campaign starts. There are plenty of reasons why one would choose to stop at Continuous Delivery. Nevertheless, from the technical perspective, the process is the same. The only difference is that Continuous Delivery requires us to press the button that deploys the selected release to production while Continuous Deployment does the deployment as part of...