This would be helpful. I would use it in two ways..

sometimes I get something that's good enough. And then I want to try some other voices or different techniques, but I don't want to destroy the work I've already done. So I want to create a copy and give it a new name.

The second way it would be helpful. is to create a checkpoint. on a large project. So that if you mess things up, you can go back to a known point.. Again, copying and renaming a file gives you the ability to do this.