Here is some brainstorming on use cases.

1. You can validate cron jobs and programmatically change or reject some of them. Or maybe just offer a small set of services as a cron job.

2. Once you have a security model you can expose this as a web service and offer cron jobs over the web.

3. You could extend this API to use different implementations of cron. Instead of calling the actual cron you could implement cron in Python or maybe use a cron web service.