Because it doesn't work like a dice game - that's the whole point, lets consider the following example:
We have a 1BTC bet, with the payout 50%, you may think that this is not a nice situation to get in the game, but actually you could have the following strategy
1. Ensure you have enough balance to make something like 5-6 bets (i.e. 5-6 BTC), lets say we have 5 btc
2. Start betting, if you have lost, bank will have 2 btc and payout will be 100% and you have 4 btc in balance
3. You can continue to bet, if you lost again you will have 3 btc in balance and bank will be 3btc and payout is 150%
4. As you can see bank and payout are heavily depend on the current streak if it is all loses - it will quickly grow, but if it all wins you can quickly recover all loses, and the more you lose the higher probability to win. Also bank grows in arithmetic progression and decreases in geometric.
5. Lets say you bet again and you win, you won 1.5 btc, your balance now is 4.5 btc and bank is 1.5 btc
6. You bet again and you won 0.75 btc and you balance will be 5.25 BTC - it is already higher than you had when you started!



So to sum up: in dice games it all about luck, here you can have some strategy, but because this is gambling no one guaranteeing that there is a strategy that will always make you money, for instance some dude could watch the site while you making these bets and he could just make a bet in between your bets and win.

And if this thing will take of, be sure it wouldn't be people who play it but bots. Lol, I was even thinking that I should take some time and release a bot at the same time with the game so that people will be equal in their chances But I already had a deadline for this thing a week ago, so I just had released it without any fancy bots