Cron jobs are a great feature to get tasks executed automatically and at set intervals. Examples where this can be useful is the import of product data into a webshop, order export to a shipping company, order details into an accounting package, user details from a CRM into a website. There are lots of ways to automate the work processes for your website.
Automated imports
In many cases an automated import is the only way to keep your site updated. Webshops are reliant on this because due the sheer amount of products it is impossible to keep products updated manually. Cron jobs are a real life-saver at this point. By setting up an import where the data is read directly from the supplier, nothing else is needed to get all the data into the site.
Automated exports
Once the products start selling on a site, there will be a need to get the orders send out as well. Running a manual export of the orders of the day can become very tedious and time-consuming. The export of orders can also be automated so your shipping & handling company will receive them in a timely manner and the orders will go out to customers.
Advantages of a cron job
Running imports and exports via a cron job also has the advantage you are not limited by the script limits when running the import or export via the browser. This allows for importing much larger files at a faster pace compared to running the import in the browser.
Another advantage is that you can be sure that the import or export runs because cron jobs are triggered automatically by the server.