Just the fact the there is a role for CM on any given initiative, program or project is a plus. It sends a signal to participants that the transition from one thing to another is complicated and difficult enough to warrant sheparding by a person rather than just through communication or project management.
As a Conduit
A CM resource external, internal or a designated leader will consider it their responsibility to make connections that are obvious, but for some reason are not happening. Leader to stakeholder and vice-versa, function to function, peer to peer across functions, internal to external resources to name a few.
As a Leadership Guide
This an extension of the conduit plus. It is difficult in organizations to get valuable feedback as a leader and to give the same as an employee/stakeholder. The CM often falls into the role of coach/mentor/advisor between the leading and the hands on work.
As a Communication Lever
In the same third party sense the communication for a change process can weave in operational interaction in a safer and more approachable manner than mandates and barked orders.
As an Organizational Assessment avenue
The process of gathering information for the end state descriptions reveals a wealth of data about the organization. Companies rarely have an avenue for objectively evaluating their people, structure and process. CM (with a good practitioner) shines a light in all three areas.
As an Operational Builder
If Change Management is an entity within the organization all of the above combined with the regular change management activities and expectations can address efficiency, collaboration, cross functional accountability and overall connection between strategy and implementation.