sorry to inform you but the gains far outdo the risks for a smart trader, with thousands of stupid traders it makes it insanely easy to predict the price within a few hours to 2 days(the weekend drop).
I've noticed this myself and it's been very tempting, but I just can't trust these exchanges. Any amount of money worth making isn't an amount I want to deposit with some random guy in Japan that gives me nothing but an email address for contact info.