Third-person omniscient is used to allow the omniscient, or all knowing, narrator to show readers what multiple characters are thinking. This provides the advantage of being able to switch between multiple characters' perspectives. The reader can then interact and relate to multiple characters, and the story can be more depthful.
N. Scott Momaday
Referencing the trail he followed to understand the tales of his grandmother.
Frequently means often.
I hope this helps.
