Understanding more about both the company you hope to work for and its competitors will help you appear competent and well prepared for the interview. It will also assist you in preparing good questions to ask of the interviewer if you are given the chance to do so.
I would assume that the author does this to show how indifferent the person in the book is, she/he doesn’t know what they are in life, this makes it relatable to readers who have had this feeling before and it shows how the character is feeling in that moment