Clarification about FAQ about DatabaseIntegrityCheck and Availability Groups

[dataflownow]

FAQ page states:

By default DatabaseIntegrityCheck is performing the checks on all replicas. This is the best practise as the primary and secondary replicas have different I/O subsystems.

Paul Randal is writing about this here.

“The lack of corruptions on the mirror‘s I/O subsystem implies nothing about the health state of the principal‘s I/O subsystem.”

If you need to control which replicas that are checked, you can use the parameter @AvailabilityGroupReplicas.

The jobs should be configured identically and be enabled and scheduled on all the replicas.

I'm confused.
Why do we need to configure DatabaseIntegrityCheck jobs on all replicas if by default DatabaseIntegrityCheck is performing the checks on all replicas?
Should this be clarified to say: "be default, DatabaseIntegrityCheck will check the integrity of any replica is runs on?"

What is the point of having a parameters for

@AvailabilityGroups nvarchar(max) = NULL,
@AvailabilityGroupReplicas nvarchar(max) = 'ALL',

in dbo.DatabaseIntegrityCheck if the job needs to be configured on all replicas?