Historically, the Vedic tradition uses the term, rishi, for someone who is inspired by the knowledge they gain to write poems or hymns. In modern times, it could be used to describe someone who has reached a high degree of spiritual awakening.
For yoga practitioners, the tradition of the rishi can be an inspiration to reach a new level of consciousness through meditation. It can be viewed as a way of awakening the inner Self and being able to see the real meaning of everything on a cosmic level.
Performing rishi's pose can help stretch the practitioner's back and hamstrings, while opening the body and mind to the sort of awakening and inspiration that defines a rishi.