It makes the imagined addressee feel more present to the reader.
Explanation:
In this poem, the author refers to his addressee as a "master poet." This master poet is most likely God. The author tells us that he cannot be "vain" and believe himself to be a good poet when he looks at how talented God is. He feels humbled by God's power and the beauty of his creations. By referring to God as another poet, the author makes Him feel more present to the reader.
I think the answer to this question is that it paved way to the popularity of mystery fiction. Also, a significant result of Doyle's detective mysteries is their focus on crime investigation and paying attention to details that would help in crime-fighting - which encouraged awareness during his time about it.
