The manager hierarchy is restrictive as it works within the business unit structure.

The rule for allocating a manager to a user is that the manager must reside in the same business unit as the user, or in one of its parent business units. So, in our example business unit structure, a user in the Central business unit can only be managed by a user in the Central, Sales, or Root business units.

The manager hierarchy is useful if you already use the manager field, for example, in your workflow.