The fact that as he states it himself, he made sure to use examples from actual writers about the actual meaning and usage of a word. In other words, he quoted their writings to illustrate the meaning of the words as they were used by actual people.
Thus, the meaning and use of the words was no longer just theoretical but practical as well. He was also very prescriptive, meaning that he asserted his opinions by using humor or judgment on the intrinsic quality of the notions the words were describing. Here that can be clearly seen by the way he uses the adjective “undefiled” (meaning not dirtied) to refer to the only variety of the English language than in his view is the proper one.
I believe the answer is to get a complete impression of the person.
It’s not to force the interviewee to give straight answers because they might be more stressed.
It’s not to give the interviewee time to think over questions because that would make more sense to give them a paper to fill out as an interview.
