It is a hugely successful program with a very low percentage of exploitation (i.e using the money for drugs, or contributing to unemployment rate). It has been constantly tweaked for the last 20 years.
You don't need to look at obscure tribal examples within America, you can just look at Australia (a very similar society to the U.S) to see this is a good policy with extremely positive outcomes for society.*
* I'll caveat this with, if you can afford it. Australia is in a super good position with regards to it's GDP/Capita and has been for the last 20-30 years, so it's difficult to say whether this is sustainable in the (even) longer term, or in countries without the same advantages.