Every casino game has a built-in mathematical advantage called the house edge. In European roulette, this is 2.70%. In American roulette, it's 5.26%. No betting system changes the probability of individual outcomes or eliminates this mathematical advantage.
The house edge represents the average percentage of all wagered money the casino expects to retain over the long term. If you wager $1000 in a game with a 2.7% house edge, you can expect to lose approximately $27 on average, regardless of which betting system you employ.
Betting systems are purely bankroll management tools. They can help you organize your play, potentially prolong your gaming session, or reduce volatility in certain scenarios. However, they cannot generate positive expected value from a negative expected value game.
The confusion often arises from short-term variance. In the short term, luck plays a significant role, and you might win using any system. But over thousands of wagers, mathematical reality prevails, and the house edge ensures the casino profits on average.