1. The media won't take you seriously pitching your own products. When it comes to publishing and self-publishing, the media especially won't take your book seriously. It will just go in the pile of unprofessional "perceptions".
2. Credibility, which dovetails into what the no. #1. You want to position yourself as a creditable professional. This doesn't always apply if you ARE a publicist. I can approach my contacts on my own projects because I have a known publicist.
3. Proper contacts -- your publicist should know who in the industry to contact. It's better when your publicist knows the media people. It makes it easier to get their attention. For example, my contacts know 3L Publishing books are first-rate books. So, when I call and put a book in front of a media person's face, that person will take it more seriously since it's got the 3L logo on it.
Do you need to hire a proper publicist? If so, contact 3L Publishing at 916-300-8012 or email info@3LPublishing.com.