Yeah sure, i can give you one scenario where it might be useful.
Suppose in some business process the organization required to perform VM Migration Operations and after joining the system into domain the system needs to be restart to apply necessary changes, but after restarting the VM user need to perform more operations on the same system.
So how can you check whether the system is restarted successfully or not.
But now you can with the help of ‘IsServerActive’ Activity you can check that system has restarted successfully.
Also you can get the last bootup time of that system as well by using ‘Server Last Bootup Time’ activity and plan to restart the system.
I hope above mentioned details will help you to understand the purpose of this activity.