I prefer strategic gambling with amount that I can afford to lose. No gmabler become suddently rich by gmabling, let alone being billionaire. But, by running a gambling site, you can definitely be a billionaire. 
are you sure? i remember some guy posted here about making a fortune off bitcoin roulette, dont care enough to find the link though. There is also the Hufflepuff case, but he was found to be cheating with an unhashed server seed. some guy also win a nice sum of ~12 BTC from sawdice a few days ago as well.