Three reasons:

1. Deadlifts work almost every major muscle group in your body.

See literally every other answer to this question.

1. Deadlifts are an extremely functional exercise.

By functional, I mean an exercise that mimics a movement you perform frequently every day in your life. And you lift things all the time! You pick up grocery bags, move furniture, lift babies off the floor or out of their cribs. Using deadlifts to practice these movements will help you continue to perform these basic actions without injury even as you age.

1. Deadlifts stimulate the neuroendocrine response.

A neuroendocrine response is exactly what it sounds like: a reaction involving the nervous and endocrine (hormonal) systems of the body.

In a stressful situation, the endocrine system induces secretion of cortisol. Cortisol then influences the production of epinephrine (adrenaline) and norepinephrine. These latter two hormones are part of the sympathetic nervous system, the system responsible for preparing the body for action. The stress required to generate a neuroendocrine response may be physical or emotional in nature.

Deadlifts are one of a few exercises that produce a neuroendocrine response. Doing so stimulates the production of the body’s anabolic hormones which leads to tissue growth and remodeling and leads to subsequent strength gains.

Sexual arousal and orgasm also generate a neuroendocrine response. And complex decision-making tasks induce the neuroendocrine response in the form of increased adrenaline secretion and elevated heart rate. That’s why training for intellectually stressful situations such as public speaking or standardized testing often calls for mimicking those very situations. These simulations allow the individual to adapt to stressors in preparation for the actual event.

Simply put, generating a neuroendocrine response is a vital component of getting stronger, improving intellectual performance under stress and enjoying sex. So if you want to get the most out of life, you should absolutely seek out this reaction in all its manifestations.

Within that context, I view the deadlift as a microcosm of the significance of the neuroendocrine response, one of the key mechanisms for improving and enjoying your life.