Btw just to add to Christian's response the DSM deals both with the transport issue (by avoiding it altogether in favour of central maintenance & controlled hot deployment) & provides the Deployment Approval workflowsto to ensure appropriate review & regression tests to go along woth that. And also test case administration to support regression testing.
So if you see a place for DSM in achieving the outcomes you are aiming for you can use features such as these to support your business case.