It seems the trouble with this idea is roughly the same reason that it makes economic sense for poor people to not have car insurance. You're playing with other people's money, and it's an asymmetric risk situation: when your bet doesn't pay off you do not have to pay the entire price, because you don't have it. So it makes economic sense to subject yourself to long-term risk for short-term profit because if/when the crash happens you're not able to pay for the damage you did even if you were liable for it. (As opposed to now when money made is safe, at worst you can be fired.)