Ideally, the larger the promotional budget and the more participants promoting the brand, the more likely it is to generate interest. Some brands only run campaigns for a few weeks due to limited budgets, but I believe this is crucial for brand awareness. The more participants and the longer it lasts the better for the casino, the casino will naturally become more famous.
Yes, the more people are exposed to a brand, the more curiosity it will generate. This will certainly lead them to visit the website, in this case the casino, to learn more and, depending on the budget, even try it out. The length of time spent on the forum is a way to build trust with users; it's unlikely you'll want to deposit money on a newly created website. I also believe that general campaigns like, signatures, social media, and articles, contribute to increasing brand visibility.
It all depends on the company's objectives and the budget available. Aside from some websites that promote it, I only see casino ads on TV, during soccer matches (that's how it is in my country), and advertising on TV is much more expensive.