Yup, completing the wagering requirements delayed the possible withdrawal if ever that you wanted to move your balance out from your casino wallet, most of the time gamblers preferred not to engage to any bonuses as they just wanted to play and walk away, though there are gamblers who knowledgeable enough to what wagering requirements are and they are okay completing to extend their chance taking free money if luck permits them completing whatever behind the bonuses.
The reason why I don't pay attention to bonus is because it comes with some requirements that will make gamblers lose at the end, one of which you already mentioned, wagering requirements is what some casinos uses to prevent the gambler from taking the bonus because the wagering requirement is too high that they can not complete it without losing it.