Why is James Earl Jones' rich baritone an appropriate choice for documentaries?

I'm doing my english assignment, and I don't really know how to explain James Earl Jones voice. He was the narrator for this Disney movie ''Earth'' and i'm doing an assignment on it. Why would his voice be an appropriate choice for a serious documentary about the Earth? Thanks for your help %26lt;3 I will choose best answer.|||Because he has a rich baritone voice