Yes there is a need. With single initiator/target zoning it is frequently implemented so that all ports from the same host are zoned to all ports from the same target. Without masking the node ports in such a zone would be used for internode. Likewise if replication is used zoning is typically done so that all replication ports from each storage system are in a zone. Again without masking these ports would then be used for both replication and internode in each cluster.
so implement port masking for all clusters. I hope this helps.