Siri was a Mentor of sorts for Obi-Wan, for a brief period of time. When they were younger, she helped challenge him and guide him during a period when he very nearly left the Order. She was also a Trickster in comparison to Obi-Wan's very rigid world view later on. She lightened moments and stood as an example of the living force - much like Qui-Gon - where Obi-Wan and others like Yoda and Mace Windu focused so much on the Force as a tool for the future. And, of course, Siri was a hero in her own right for her own world view, though we only saw her as a minor character in Obi-Wan and Anakin's world. She sacrificed her reputation (for a time) when she feigned abandoning the Order and took up as a spy for a smuggler. And she later sacrificed her love for Obi-Wan in order to stay true to the Jedi way and to help those who needed her. Ultimately, she died as a hero - sacrificing herself to protect others.