On a European wheel, there is just one extra pocket (the single zero), which sets the house edge at 2.70%. These payouts are mathematically designed to be 100% fair for a wheel with 36 pockets any extra pockets give the casino the advantage. The issue comes from the fact that both games offer the same payouts for all bets.
Unfortunately, this is universally a bad thing for players, which means that when you have the choice, you’ll probably want to play the European version. The American roulette game differs from its European counterpart in only one notable way: the presence of two zeroes on the wheel instead of just one. How Is American Roulette Different to European Roulette?