If the implemented tax doesn’t reduce the number of gamblers or their activities, the government will gain more income. But if it ends up discouraging people from gambling, then their revenue will decrease, and I’m sure they’ve done some studies before deciding to implement it.
Those who are addicted will continue with their gambling habit. Those who are new, as in seeking to find a way to earn money will get discouraged. It is a known fact taxation does create an opportunity for those who are smart. It does disrupt those who cannot enjoy this opportunity. Those who make money are those who have money, whereas it works the other way for those who seek gambling for earnings.
As you mentioned, it’s a third-world country, and in such places, people are often desperate to make money even if it’s through gambling, which many see as a risky or “wrong” way.
It is not desperation, it is an option to survive the hardship. While, I am not an individual promoting gambling, I still believe gambling is one of the options to enjoy your life without contacting your friends who are always ready to degrade you, as in yourself.