Chat cloning would be useful if I wanted to take an ongoing conversation in a different direction but didn’t want to mix up the existing algorithm, conversation, or anything else that had been built up so far.
For example, if I’m working on a more complex program and think of a new feature or for some other reason want to fork it, I wouldn’t want to continue this on the original branch. I would clone the chat and add the new feature in the cloned chat or take the development/conversation in another direction.