Throwing down piles of cards, no matter how eye catching, is a mixed bag at best. For every 100 or so cards that get absent mindedly grabbed, you get 1-2 inquiries, and those are usually from individuals, not companies looking to hire. Be an individual, not a business card, and you'll find a place that wants to hire you and not an image.
I wasted way too much time and energy on the self promotion game to ever advise anyone to do the same, and honestly, glad I didn't end up getting lucky in that arena, the industry is full of random lucky types who spend most of their time convincing themselves and projecting to the public that they're worthy of their own hype, the companies that fill themselves with people like that tend to be quick to peak and short lived.
Yet at such events, a soft spoken person who provides quality will be lost in the crowd 9.9/10 times, that was me. Better product, better cure, better concentrate, better everything, yet because I wasn't dancing around like a 20 something spouting the latest instagram slang, I was ignored. Social media is poison to quality, both in product, and in people.
