[jlouis]

In large setups, it is usually clever to isolate job execution policy into a separate system. This simplifies a lot of contextual configuration of the system at large.

You can have cron emit the cascading event if you want but you often need a system which can "prod" other systems and ask them to do things because of a timing event. In such systems, cron often falls short as the system around it grows.

For local timing of events, cron is a really good tool however, and I wouldn't hesitate about using it there. It is for system-wide events these general job schedulers tend to help.