In your opinion, does advertising require more knowledge about the product being advertised, or an extreme amount of creativity?

Given both criteria defines the so called advertising per se. Both must go hand in hand in order to reach and attain  its own purpose.

I think it need both more knowledge about your product and how can you link it culturally with the audience in a creative frame  ^>^

I think advertising requires deep knowledge about the person(s) supposed to view the ad and eventually purchase the product. Creativity is key, but would you purchase a product because the ad is highly creative? Unless it appeals to a part of my brain that says I want or I need this, advertising has a short time slot in our working memory.