What is Kubernetes' Users for? : I'm studying Kubernetes now, and have a question about Kubernetes' Users.  
I learned how to create Users and how to limit access by Role, but when should I use it?  
I mean, if malicious user(not k8s user, but operating user) penetrate k8s server, they can switch administrator easily (if they can see .kube/config).   
In addition to, if user switch his user account and he forgot switch back, the another person who enters next can also use first user's account.  
I doubt if I misunderstand usage of k8s Users, but it seems to be no documents about why k8s prepared it.  
I slightly assume that Users only use for doing something from inner pods, but if so, what the difference between Users and Service Accounts?