. I was wondering what is the use of 

PipelineController.create_draft

 if you can't use it to clone and run tasks, as we have seen

I think the initial thought was to allow to create a pipeline from a pipeline programatically. Then once you have the "pipeline" you can manually enqueue it and modify it. Think a pipeline constructing other pipelines in flight based on some logic, then launching them in parallel.
make sense ?