It will. The one that has paid them will really get more visits and sign ups due to their influence and attraction. But it will depend on how they will get to make their audiences and fans sign up into that casino.
Because if they are not convincing then they won't attract a lot but there's a reason why a casino has chosen them to advertise their website because there's a character that they've liked on that influencer which will help them.
If those influencers can show the video that almost looks real, the audience will follow them and sign up to that casino and spend some money because the audience will have a will to be like the influencers. It is about how they can convince the audience to follow them and they already did with the previous audience and sent them to the casino. Maybe the new people can easily visit the casino and see if they can have a chance to win as what the influencers got. But if they are only curious about what the influencers said and then did not have a big intention to continue playing, the audience will not stay for a long time.
Usually, many of their videos look legit and the way they convey messages to their fans, they look legitimate. And that's why the audiences have to look if the video is just made as sponsored because that's what has been happening.
Looking for the bets that they do, you don't have to wander about it because they've been sponsored and they are obviously fake and whatever amount they win, it's just part of the act.