Automation is the second pillar of the DevOps CAMS model. DevOps uses a lot of continuous practices to achieve speed and stability, and to be able to be continuous, you need automation. You automate the CI/CD pipeline with DevOps tools. The build and testing process is automatically started, once the developer checks in the code change on the main branch.
With automation, we save time for more important things. It is also a way of creating consistency, preventing defects and enabling self-service.