There are at least two major reasons that this trail was significant.
First, it served as something of laboratory for westward expansion. A great deal of commerce was conducted along this trail. By doing so, people learned about how to use heavy wagons for crossing the plains. These techniques would later be used on the Oregon Trail and other ways west.
Secondly, it can be said to have led to the Mexican-American War. American traders on the route found out a great deal about that area of what was then Mexico. They learned that it was very weakly controlled. This helped to encourage Americans to move into that area and helped to make them feel they might some day take it from Mexico.