You said they have chance if they offer best price on the market problem is most of them create their own block chain that means if someone wanna bet he first buy bitcoin with a fee transfer it to exchange buy their coin with a fee than transfer it to their website 2 reason thats not gonna work out even if they offer the best odds these transfers ended up as loss for who is betting and they dont like complications. They want fast and easy experience their concept very far away from that.