According to Tara Golshan and Arthur Delaney, one of Joe Manchin’s objections to providing cash benefits to the children of low-earnings parents is that those parents would waste the money on vices:

Publicly, his biggest gripes are about the cost of the bill. But privately, Manchin has told his colleagues that he essentially doesn’t trust low-income people to spend government money wisely.

In recent months, Manchin has told several of his fellow Democrats that he thought parents would waste monthly child tax credit payments on drugs instead of providing for their children, according to two sources familiar with the senator’s comments.

This is a common objection to these kinds of benefits in society, but not one you usually hear in elite political discourse. It also happens to be a baseless objection that neither reflects the reality of what happens when you provide people cash benefits nor solves the problem of irresponsible parents.