Orion Platform can provide with details of user (local & Remote) the last login and current privileges but not audit friendly. ARM can do a good job in identifying local & AD user and verify the current status of user on AD and also the group information to monitor & validate the associated privileges on Orion platform.
Orion Platform provides not just Monitoring but also Management capabilities via modules like NCM. ARM can help secure the Orion Platform from unwanted user.