It is underestimated the value of proper alignment in yoga practice. It is of great importance to understand and develop awareness during asana practice, meditation and Pranayama.
There must be permanent awareness of the position of our head, shoulder girdle, arms, spine, pelvic girdle, legs, feet and last but not least important, our breath. It is critical to really comprehend the objective of each posture. Otherwise you might waste your precious time doing something that will not ripe optimum results, and possibly lead you to quit your practice.
Meditation and Pranayama, besides having powerful positive effects on our mind and the way we manage life, we also develop consciousness on the position of our spine. By holding a proper sitting position and working with our breath we elongate the spine and create space between intervertebral disks, which often compress against each other.
We become victims of our own habits developing chronic conditions like the Repetitive Strain Injury (RSI), which is developed by repetitive tasks (wear and tear), or exertion of pressure on passive postures. By becoming aware of this you can prevent and improve undesired physical conditions.