Specifically, more atomic commits make rollbacks easier when issues with a change are discovered after merge (e.g., in integration and user acceptance testing). In the very active code bases I've worked on, generating a rollback commit for a single commit is far more straightforward than having to deal with a merge commit that potentially includes other merges (e.g., with `git pull`'s default behavior). In fact, GitHub's pull request UI has it as a single button.