I believe mentoring is important because it greatly expands and diversifies the pool of personal experience that each of us can learn from.
I grew up, and started my research career, in the Soviet Union, and lived and worked in Canada and USA for 15 years before moving to Australia. In 36 years after getting PhD, I worked in organisations of four different types: an institute in the Academy of Sciences system, a museum, a federal geological survey, and now a university (ANU). At some point I also switched from chemistry to earth sciences, although never stopped being a chemist. So a lot of moving and switching experience to share.