House Edge

The house edge is the casino's mathematical advantage on each bet, equal to 100% − RTP. With a 96% RTP, the house edge is 4%: on average the house keeps €4 for every €100 wagered over the long run.

It is a structural, transparent figure, not a "trick": it exists in every gambling game and is what makes it economically sustainable. In the short term volatility can let the player win, but the house edge is why gambling should be treated as entertainment, not a source of income.