If you are in the SEA region, pretty sure they advertise everywhere, with Pacquiao and many other local celebrities.
Of course, in the global casino market it is extremely difficult to somehow compete with the leaders of this market, about which everyone here is well informed. And occupying a regional market niche is a logical development, entailing a successful casino business.
Most likely, you are right that in percentage terms there are more players from the USA, EU, as well as from Latin American and African countries. But the SEA market is also huge, given how popular gambling is in this region.
I believe it is not difficult to compete here in the West, there is a very large portion of the betting market that has not yet been filled. And in many cases, customers who are from one bookmaker also go to others because of the odds. But when it comes to Asia, it is really something much bigger, due to the population and the popularity of sports that are better seen in the West.
Most middle East countries have low penetration of their market and that is because of the religious beliefs from that part of the world, although alot of things are changing right now and even gambling acceptance too will change as time comes.
In the West, we have the eternal good example of Las Vegas. Countries here should have their own "Las Vegas" in their country too. If it is harmful, the necessary measures should be taken, but this should not prevent people from playing responsibly in a city that is only for gambling, casinos, etc.