Getting around the clip library locking is not simple. No matter what, a call to the WT server will have to be made to create the new clip when the user is not using the library. I suggest a workflow with in and out boxes to allow the artist to have read-only access to clip libs you push to it, and vice versa, to allow the artist to write to clip libs from which you will pull media.
As for the difference between using WT to push job, and using the new BG IO tool, the big difference is that jobs are managed by a job manager (BackBurner), and can be queued and controlled better than a command-line tool or embedded operation. There are also image processing options. Finally, BG IO is arguably faster than what the average WT developer could achieve because disk IO, network IO, and CPU operations are all executed in parallel.