Yes, that's true and I agree with what @Cling18 said because sooner or later, social media can ban advertising about gambling or limit those ads. This all depends on the policy between social media and the government. But if the promotion was done on a crypto forum, I think it could hit the mark more because casinos use crypto for payments and bets. Every casino will try to promote their casino on many websites and if they can promote in this forum then this will be even better.
There are different strategies of promote. But in all of them the promoter have first of all to sit and to make research. He need to know who will play, the age of players, average bet, what games will be popular. After he get this information he can decide what advertise he need to choose - sometimes this is signature campaigns on crypto forums, sometimes social media, sometimes, may be TV. Different situations and different ways of advertise.