The single bet is good as it means you are only betting on one outcome rather than multiples, where you need a number of results to be paid out. Single bets can be used on a favourite that will have low odds or can even be odds-on, or on outsiders with larger odds that can potentially pay out bigger winnings.
1xBet requires you to wager 50% of the bonus amount five times in a minimum 3-fold accumulator bet, with at least three events having odds of 1.40 or higher. Additionally, the other 50% of the bonus amount might need to be wagered 30 times in 1xGames.