If I do not desire anything and I am not afraid of anything, then the mind is quiet. Not asleep or chewing its cud, but alert, watchful and ready. Like a top-of-class majordomo.
A quiet mind is a powerful tool. So is a cordless drill.
In order to use the drill, the drill must be off. If some mischief-maker locks the trigger, and the drill is madly spinning, the drill is useless. It must be “off” before the screw can be set. And, properly, it is “off” vastly more than it is “on”.
Ceaseless thinking is a morbid activity. It hastens dementia.