DZone
Why Namespaces?
Kubernetes Namespaces can be used to divide and manage a cluster, segregating the cluster for use by different dev teams or for different purposes (e.g. dev and prod). Namespaces can be a focus for role-based access control, with the option to define roles as applying across a namespace. Resource quotas can be set as specific to a namespace, allowing specific namespaces to be given higher resource allowances. Sometimes one will choose to use distinct clusters for different purposes but if the purposes are related then namespaces can be a more convenient or appropriate option.
Source: DZone