Sitting a lot and practicing in the right posture requires muscles to do a lot of monotonous holding work, which over time will manifest itself in inflexibility and associated pain (e.g. tension along the cervical spine radiating into the shoulders, resistance in the lumbar spine, pain in the forearms).
Yoga is a kind of moving meditation; a way to be flexible in mind and body and firm at the same time; a method for releasing blocking elements in the body, allowing us to become freer and more joyful. We use our breath, self-observation and appropriate exercises to maintain flexibility in our muscles and fascia.
Yoga = release and reconnect.