Sometimes, one wants to make sure that when an app is exited, it's also killed, ie it will not show up in the task list and can't be re-entered, for security reasons or privacy reasons. Sometimes, one does not want someone else to just pick up and continue where one just left off, or perhaps even to be able to see that the application has been used at all.
I've tried ExitApplication, but it didn't have the desired effect. It's possible that it is destroyed, but it's still in recent tasks and restarted when I click it.