Unfortunately you have gotten the wrong mindset, it's highly unlikely that they stole $20 - but you are simply destined to lose all your money by playing such games. They are quite simply engineered to benefit the casino, the casino is not a charity there to hand out free money and there is a reason that last year was the best ever year for gambling company profits. Every single game you play is statistically calculated to return a commission to the "house" each go. You might win game one and game two, but they know that a true gambler will always pay any winnings back to them because the whole activity is heavily driven by greed. Blockchain gambling might reduce the commissions but there are always expenses that will have to be paid by every person betting over time.