People are attracted to self confidence, because most of the time people who are openly confident (down to the minutiae of body language) are in a position to be confident. The ability to simply be insensitive to the normal stresses and worries that would inspire rational doubt can put you in a position to lead.

Of course, you'll be leading with coin flips, and most people will fail. We just pay special attention to statistical flukes who make a lot of money before they flip out.