The purpose of ashtanga yoga is to gain a one-pointed mind. This is what it says in the Yoga Sutras of Patanjali. To have a one-pointed mind means you are free of compulsive conditioned thinking. To get there we need to train our mind to focus only on matters we choose and stay there. This is not easy. The ashtanga asana method is a practice system that when used correctly can arrest our mind. This is because next to focus on breath, bandhas and drishtis, there is not much time for random thinking. To be effective this practice is to be performed 5-6 days a week for a long time - preferably for life. In this way we are creating a new mind pattern that in time will enable us to focus and keep the focus on a subject of our choosing. This is also called meditation. It will set us free from the constant and often negative mind chatter in our head.
Asana practice is just part of the way to achieve this but it is not the only way. Yet, the asana system of ashtanga yoga has been mutated into a yoga form just by itself. It has its own industry, community, rules and regulations, kings and queens, global events, tv channels and plenty of stuff to buy. The yoga community bickers among another, people are mobbed, discredited and punished for not obeying rules...... just like in any other community. This is the work of compulsive and conditioned thinking. It is the pattern of the world. The pattern we would like to get away from which is why we are doing yoga in the first place.
It is not surprising that this asana system has become so popular. On a purely physical level, this practice increases strength, flexibility, stamina and overall health. I love my asana practice! It is beautiful to do and to look at. Once the system has been learned you can do it alone at home, go to a shala or join a practice group. You can discuss and compare your 'progress' with others. You can hunt and excel in certain asanas and show off, be better than others or even be the best....
Still - we should not forget its purpose and its place in the overall Ashtanga Yoga System. The aim of this practice can be achieved with the simplest of asanas, even with easiest beginner version of sun salutation A, if practiced mindfully, for a long time and in harmony with the breath, bandhas and drishtis. We are clearly exaggerating the importance of asana. Taking it too serious. We are overegging the pudding and as a result our mind is stiffer than before. Ashtanga people can get very intense. One wrong word can set of a mighty shit storm. But this is how it is - the pattern of the world.