It depends on what country you live since here in Philippines facebook dominates all the social media above while X is on the last place for popularity at least for me and my social network.
However, CMIIW US and EU use X more often than facebook. So the ranking on social media strength varies based on what’s the preference of each user.
Irrespective of the platforms, the marketing team who are professionals will know how to go about with their promotional contents that best suites the audience in these countrles.
If your budget for marketing is not big enough the casino will prioritize it.
Another point to know is that promotion goes far beyond the social media platforms we still have other internet and gambling forums where gambling discussions take place.