First this is NOT related to character history.

GetPlayerHistory()
SetPlayerHistory()

This is used for events that need to be stored for the character, they didn't seem to fit in with character history to well so these function were made. A few examples would be in an instance when you read a note to get access to a door, every visit after that you should still have access to the door. Another would be a quest that is not an actual quest, no journal entry nothing, this would let you keep track of the steps and progress.