We use it to manage our batch processing. For us, it came in as a replacement for a lot of different systems running crontab. In our case it's primarily for Unix/Linux systems that don't have their own mechanism for kicking off all these batch processes. It's the coordinator of all of our background processes and batch jobs that are running overnight and during the day.
We use it to kick off custom Unix/Linux scripts that will launch our application processes. It's almost entirely Windows and Linux shell scripts that it's kicking off.