The cronjob is new to the Twitch Stream software. It allows for a fast website without interuptions from API calls. On the MS Twitch Stream software those API calls were made by visitors on the website which can slow down navigation a lot. SD Twitch Stream has a cronjob now which retrieves data from the Twitch API without disturbing or ruining the visitors experience on the website. It caches all data in the database which makes all extensions found in this package lightning fast! The database is optimized for fast reads to improve your site speed in comparison to MS Twitch Stream.
Configuring the cronjob is very easy. It is explained in the backend component of SD Twitch Stream. If you do not know how to setup a cronjob or your hosting won't allow you, you can always use the webcronjob! The webcronjob is not recommended as it opens a resource-heavy url on your website (although a lot of the cronjobs run timebased).
The cronjob is not required for websites that only require an embed (this disables the "hide if offline"-feature too).