The key observation is that a study published in Nature "found a correlation between child brain structure and family income. Simply put, family income is correlated with children’s brain surface area, especially among poor children. More money, bigger-brained kids."
This is supported by the Cherokee study: when the families became a bit better off ($4,000 a year) the kids did better when they grew up.
So it's missing the point to argue about how grown-ups might (or might not) "waste" money and whether cash is better than other forms of welfare. The point is that bringing up children in poverty creates a worse outcome for society as a whole.
The fact is that $4,000 a year for 20 years is a very small amount compared with the cost of US police, courts, and prisons. If a poor kid grows up, gets a job and pays taxes, that's a massive win for society compared with the same kid growing up in the sort of deprivation that leads to a life of crime and jail.