Traditional sportsbooks have your address, your phone number, your email address, and more info about you. Some sportsbooks sell your information to list creators. Those list creators sell the info to tout services that call you to get you on board with their plans.
Well, apart from Web 3 casinos, other online casinos also request for customers original details during registration and KYC verification, just as the traditional casino would also request those details. Cryoto casino that allows gamblers to use the casino without knowing their original details is only on Web 3. There are some regulated crypto casinos or shady crypto casinos that can actually get customer details and sell them to scammers, or the casino could either be hacked and customer details could be leaked.