this is very risky to played BTC casino ,most of all you need a big money for that gambling
That's how gambling works, imo. No matter wherever you play and which currencies do you use (even with fiat currencies), there is no 100% guarantee that you will win the game. There is some percents possibility that you will lose.
most of all you need a big money for that gambling
I don't know from where you got that conclusion but as far as I know, there are plenty of gambling/casino sites that can be played with small funds even with a cent.
No, it's almost impossible to hit the jackpot, but it's more likely to loose a certain amount of coins. I try to avoid both betting and casinos.
But it still possible, such as what I did a few months back on
this site (for now not recommended to play here until their problem solved).
Gambling is not about hitting the jackpot. Treat it as an unexpected bonus you got, don't force too much to hit it or you will end up with lose everything your funds.
It would be better if you play as usual and enjoy the game.