Why does the Torah tell us this story?
The Ohr Hachaim explains why the Torah needed to tell us this entire conversation and discussion between Yisro and Moshe.
Hashem wished to teach Klal Yisroel, in that generation as well as future ones, that there are wise people among the nations of the world. Yisro used wisdom and understanding to establish a justice system for Klal Yisroel.
This is a lesson to Klal Yisroel that the reason they were chosen and received the Torah is not because of their intellectual prowess. Other nations also possess wisdom, yet Torah is ours.
This is especially understandable according to the opinion in the Gemara that Yisro arrived before the giving of the Torah. Yisro served as a lesson to Klal Yisroel to understand their true value to Hashem. Not due to their heightened intellect or deeper understanding. Only because Hashem loves us and the connection our forefathers had with Him.
For this alone we need to thank Hashem. We were chosen out of pure Divine love, nothing external.
