The following description of the namespace, which one is wrong?

Kubernetes The cluster has three by default Namespace: kube-system、kube-node and kube-publicB. Kubernetes provides namespaces to organize and divide resources, and use multiple namespaces to divide systems containing many components into different groups

When there are many users in the team or project, you can consider using namespaces to divide user resources

Namespace can only be organized into divisions, and for running objects, it cannot do the real isolation