Practical use case of 'git rm' and 'git mv' with git?

I know that git provides the 'git rm' and 'git mv' to remove/move files or directories. But, I can't see the practical use case for this.

Normally, I just mv or rm the files or whatever in the command line, and after I'm done with all the necessary actions, I can just run 'git add -u' and 'git add .', as I asked and got answers in here.

Am I missing something? Are there any cases that only 'git rm' and 'git mv' capable of?