Can System Status be used to kill other apps?

No. Because of the security restrictions of iOS, it is not possible for any application (including System Status) to kill other apps.

You can, however, use the standard iOS way to close apps — open the app switcher (swipe up from the bottom of the screen and pause, or double-click the home button on devices that have one), swipe to the app you want to close, and drag its screenshot up.

You can also use the ‘memory release’ feature of System Status to close several apps at once. However, there is no control over which apps will be closed to free the memory — this is controlled by iOS.