Frankly speaking, when I was first introduced to this approach of the Ashtanga system I was antagonised.
I love theory. I enjoy exploring, developing and analysing the complexity of situation and I even do it for a living under my design lecturer hat.
However in design, a profound exploration of a great concept doesn't stand for itself, it should be applied into the design creation.
When it comes to yoga, understanding and discussing in the theoretical level is not enough.
How to understand the concept of Pratyahara, redraw the mind from the information provided by the senses, unless experience it ?
Even full understanding of the concepts of Yamas & Nyamas, yoga ethical codes of conduct, can not remains in the theoretical level, daily effort on the mat and out in life, is needed to change the automatic response of the mind.
In the Ashtanga practice there are movements and poses which cannot be learned by reading a book or by explanation, understanding comes only from consistent practice of the required skill.
To me ’99% practice, 1% theory’ doesn't mean not to be bothered by theory.
It does mean, learn theory but spend 99% of your effort on applying it to your practice and life, and only 1% effort on studying it.