What do you mean? It showed two batches being copied in parallel. If anything, they should do less in parallel and rather queue up jobs between same disks.
Yes, you can have multiple copy operating running in parallel but the way Windows works, the files themselves are copied in serial order (within an individual copy operation). Whereas with tools like RichCopy, you are actually copying multiple files in parallel.
I'd be interested in seeing benchmarks that demonstrate an improvement when doing this. I'd expect that the average case is slower due to increased disk contention.
See here for example; http://msinetpub.vo.llnwd.net/d1/keithcombs/blog/images/Rich...
This is incredibly useful when you need to copy folders with a lot of (smaller) files. Think pictures, music, etc.