How is historiography a useful tool in studying religion academically?

Historiography is the study of historical writings, to determine the motives, circumstances, and biases that might have affected the person(s) writing that version of history.
How is historiography a useful tool in studying religion academically? What about for people of faith, hoping to deepen their own religious practice?  Is historiography a useful endeavor, or is it a problematic, disappointing, or upsetting method for people of faith?
Elect to respond to this discussion question with a 3-4 page essay, typed and double-spaced.  This essay must reference at least one reading (Attached).  You can cite the materials informally, using author last name (i.e. no need to use MLA citation format, etc.).