I am from Venezuela, a country which has been suffering a economical crisis for years now, to the point there are millions of people who have decided to flee this country and spread around the world. We don't only suffer from an economical disaster, we also have a very corrupted and autocrat system where the military is at the top of the power management.
I assume it is not only about the number of gamblers, but also it may have something to do with sanctions the United States and the European Union have imposed over this country. So stake does not want to get in trouble with any western government, only allowing people from here to deposit through Bitcoin and other alternative cryptocurrencies.
I also think it would be a hassle for Stake to try to keep liquidity and manage our local currency, which is always losing value...
They do allow tokens that drop in value, like $Trump, so i am not sure if it's about volatility or price drop. I would have put my money on being in restricted countries, but i guess they are not on that list.
I have heard that people in Venezuela rather prefer some other currency themselves, so maybe there's no demand for that currency. It would be the simplest explanation imho. Also new fiat money is always extra hassle to deal with. Unlike crypto that works 24/7, even if some country would have problems with their infrastructure.