Answer: When you can appreciate the author's choice of more serious words, even if they are challenging to understand, you realize that the author is writing to a more mature audience and the tone is supposed to inspire confidence in the writer's credibility. You grow as a reader when you become more familiar with those word choices.
Explanation: An author can choose whatever words s/he wishes to help the audience feel inspired, entertained, enlightened, angry, disturbed, or disgusted-- or any other mood that may result in their understanding the author's purpose and theme. The writer can make an impact on the reader-- a memory, a change in thinking, possibly a life-changing decision.