Why is merging user stories' feature branches into the promotion branch important?

Merging user stories' feature branches into the promotion branch is crucial because it allows changes to integrate properly into the destination environment. This integration is essential for ensuring that all contributions from various feature branches are combined and tested together before being deployed. By merging into the promotion branch, teams ensure that the final product reflects the entire range of updates and features developed across different user stories, which helps maintain the integrity and consistency of the codebase.

This process mitigates potential issues that could arise when features are deployed independently, ensuring that all components work harmoniously in the target environment. Proper integration also aids in continuous delivery practices, enabling quicker deployment cycles and reducing the likelihood of merge conflicts during subsequent changes.