It all depends. Online Slots are extremely fast and with high variance. You can theoretically make a few thousand euros from 10c but you can also lose a lot of money in a short time. In addition, online slots gives you the opportunity to unlock a casino bonus, which is not available in games such as blackjack or roulette. Blackjack is an extremely fair game. Provided that you have mastered the optimal strategy to some extent. Then you can play Blackjack with practically no house advantage and lose no money at the end of the day. At least playing Blackjack is a lot of fun. Roulette is above all a game where you can try out some strategies. Whether Martingale, Fibonacci or others. It is always fun to see how the theory works in practice. But you should know: Roulette is not a game that you can actually beat with any system.