Occlumency is undeniably a powerful tool. It can save you in many ways. Not only when facing an enemy, but also on days when even you are wondering if you deserve your next breath. You can get rid of all the unpleasant thoughts, push them away, segment them and then banish the individual components to the furthest corners of your mind. You can lie to someone's face without worrying that they'll see through you. Even an escape can be planned and no one will ever know. Occlumency sharpens the senses, makes you tough and efficient. Yes, it might even literally save your life one day. But if you use it day in and day out just for survival, it cuts the soul into pieces as much as it preserves it.