Making configuration changes manually or without using proper configuration management tools can result in inconsistencies across different environments. For instance, a developer may update a configuration in the development environment but forget to do so in staging or production. This "drift" can lead to software bugs, failures, and difficult-to-diagnose issues during deployments. Configuration management tools automate these updates across all environments and maintain a single source of truth for configurations. This ensures all deployments are consistent, traceable, and reversible, which is crucial in a fast-paced CD pipeline.