We added the ability to create a Broadcast Wave deliverable in v1.5.4 b5495.
You could always output one in addition to certain other deliverables like DNxHD, DPX and ProRes. But now you can output it alone.
This can be a useful way to export the audio from any file if you want to bring it back in and sync it to your picture either because the embedded audio is slightly out of sync, etc.
Other cases we have seen where it can be useful is when certain deliverable specs require a broadcast wave to be delivered with a different channel mapping from the main deliverable.