The issue is that the vast majority of brokers set unrealistic expectations. The average user does not get such results.
The most common way binary brokers attract new traders is to show them examples of how ordinary people have won large sums of money by trading small amounts of gold and other popular assets.
True, such cases do exist, but they are the exception rather than the rule. In the same way that some sports gamblers can win extremely large sums of money, skilled/lucky binary options traders can occasionally make money. However, this is extremely rare.