1. Many folks are really computer illiterate beyond internet surfing and basic computer usage. If you show them a few tricks- you create the same effect a magician has on kids. People get mesmerized.
2. You can really fool people by marketing campaigns. "Best selling author" , "Helps crack emails for intelligence agencies" etc kind of campaign forces people to ask "Why would so many people buy his books, unless he has something genuine to write" - Hence increasing the books sales in this cycle.
A relative of mine did a ethical hacking certification from this guy. He showed it to all other relatives like waving a flag out of pride. Nothing that I told convinced the audience as to why the certification wasn't even worth the paper it was printed on. It was all like they were asking me to shut up and stop spewing negativity about it. They were like "At least he learned something through the certification".
3. Job promises and resume decoration, If you tell some one your are a certified ethical hacker. Ordinary joe, who knows nothing of the topic will not only believe you but rather offer you job over say an actual ethical hacker.
4. We like degrees, certificates and titles next to our names.
And lastly we just love famous people. Even if all they do is nothing. Bollywood is full of such examples.