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I don't think this could be effective marketing unless and until the video uploader is famous on YouTube and have a lot of followers. Also, he should have a channel related to crypto gambling and casinos. I have seen many bounty hunters make videos but no one views their videos and channels. Better contact an influencer if you want to do marketing through videos and you may have to spend some money in order to ask a famous youtuber to make a video on your gambling casino.
Marketing, specially in big businesses like gambling business, they use both elements to have a effective advertisement of their casino/sportsbook.
They can hire someone known in the platform to upload their advertisement, however I think that is not professional. As a business entity you have to have your own platform where you distribute your way of communication with your customers. Better if just partner with these celebs/streamers about that, plus have a really good video output.