There was an influence on the other Kagyu traditions. One of the Shamar Rinpoches wrote a commentary on it. These days it seems little known outside the Drikung Kagyu. I believe that Chetsang Rinpoche revived the study of it, prior to that it was not much studied in recent times.
The Gong Chik is a collection of sayings by the founder of the Drikung Kagyu, Jigten Sumgon. Some of the sayings go against commonly held Buddhist teachings, such as pramana (buddhist epistemology) teaches the ultimate truth. (Quoted from memory, not an exact quote.)
Lamrim, lojong, and mahamudra are the unmistaken path.