Searching to launch an application is a habit, not part of the task of actually launching an application.
Likewise, closing an application is a habit and also not part of the task of using an application.
Designers seek to optimize tasks rather than what people have learned to do. Otherwise, there would be no progress and you'd just be retaining something that just doesn't make sense in the current context. For example, in an app-centric world, does it make sense to have to open and close 12+ apps in the same session?