That is the equivalent to asking whether it is more important to study philosophy or religion (the development of the beliefs not the beliefs themselves). History is what "happened" where as historiography is more analytical of how history has become distorted when written. So, historiography allows us to better understand what actually happened while history is the study of what supposedly happened. In other words, in history, you study the past in the most factual way; in historiography, you study how past historians recorded history and how they were biased.

Using the popular quote "those who do not understand history are doomed to repeat it," if a politician was to understand historiography then they would understand what to do in order for them to be remembered for the longest time, but if a politician understood history they would know what to do to have the most impact on society quickly.