The "zero" in Roulette plays a crucial role in influencing strategies by introducing a house edge that hampers players' chances of consistent winnings. European Roulette has a house advantage of about 2.7% due to one zero, while American Roulette, with both a single and double zero, has a higher house edge of around 5.3%. This advantage impacts betting systems, as not all bets pay even odds, leading to a decreased likelihood of long-term success. As a result, players need to factor in the zero when formulating their strategies, often necessitating a more cautious betting approach.