Gnana Yoga is all about accumulating knowledge through learning and knowing the self. This path focuses only on knowledge acquired through learning only (and not necessarily experiencing the subject matter).  So the knowledge is acquired through rationalization and concluding on the relationship between cause and effect.  So the Gnana Yoga practitioner is an academician.   Essentially, the practioner should necessarily be well versed in the Veda, Shastra and Scriptures and would be a person with adequate intellectual capability to retain the material in his mind and would be able to quote from and expound on the works with ease.

The following is an extract from Wikipedia:

Jñāna yoga is knowing beyond name and form through pure understanding of the nature of doer, who when seen in clarity results in liberation. This path is different from other forms of Yoga in a sense that other form emphasizes on a structured way of experiencing reality through a process of crystallization carried by doing different forms of meditation. However this path simply states that only knowing is enough. It many a times draw parallels to Samkhya as well. As used in the Bhagavad Gita, the Advaita philosopher Adi Shankara gave primary importance to jñāna yoga as "knowledge of the absolute" (Brahman), while the Vishishtadvaita commentator Ramanuja regarded knowledge only as a condition of devotion.^[3] In the Bhagavad Gita (13.3) Sri Krishna says that jñāna consists of properly understanding kshetra (the field of activity—that is, the body) and kshetrajna (the knower of the body—that is, the soul). Later in the Gita(13.35) Sri Krishna emphasizes that a transcendentalist must understand the difference between these two.^[4]

As would be evident, the lifestyle and capability of each individual may not be conducive to this path.  Not all of us are blessed with the capability to grasp and the capability to retain and the capability to relate the different pieces of the oceans of knowledge the the physical and meta physical world is comprised of.  

This is why alternate paths have been created, to suit the capabilities of each one of us. 

Ultimately, all the paths lead to the same destination.  From this aspect, there is no difference between them. 

Krishna Paramathma says in Srimad Bhagavatham:

“A Man’s wealth of learning may be immense. But it is not enough if it is just an accumulation of the learning of the Vedas and the Shastras without being leavened by the stories of Me and my Avataras.  Uddhava, I know that it is not easy to devote one’s mind completely to Me and to thoughts of Me. Such a Man can do Karma Yoga: meaning, let him perform actions in the World. But let him not at any time desire the fruits of his actions. He should not expect rewards for his efforts. Let him act like this in the World of Men and let him think on Me as often as he can and he will soon become my Bhakta and he will reach Me.”

Kapilas Teachings -II

"It is the Brahman or the Purusha or the Ishvara or the Bhagavan according to the different Yogas which seek Him:  it is this which is revealed in all manifestations in the world of plurality.  The one who realizes this is the Brahman himself.  Realizing the Brahman is not a Knowing but a Becoming.  You will KNOW that you are the Brahman.  The Jiva will know that he is the Isvara, the Purusha.  The Gnyana Yoga taught by me and the Bhakti Yoga on which I elaborated earlier, are in reality, the same.  One is not different from the other."

Kapila's Teachings

When the feelings of "I" and "Mine" disappear, the mind at once becomes free of Kama, Krodha and other qualities.  It becomes pure and is fit enough to lead you to me.  The Pleasures of the world and the Pains will not affect it anymore.   When it is equipped with Vairagya,  detachment or rather non-attachment:  with Bhakti which is devotion to me: and with Gnyana which is knowledge of the truth about me,  then the mind is able to perceive the BRAHMAN".