Probably like the earned income credit, where some on the lowest tiers get more money back than they were taxed in the first place. Just a disguised welfare check.
They are assuming some families will get the child tax credit and paying it out in advance by month. My DIL claimed the child tax credit last year (separated from my son). I’m betting she received it IN ADVANCE this year - although the kids have resided with my son in a different state the entire year. So as I understand it, she’ll have to PAY IT BACK at tax time! Started in July, so half of $6,600 - or $3300 she’ll have to PAY BACK.
That is unless she files a false tax return and claims the kids resided with her. Their attendance in school 1,000 miles away the entire calendar year will make that a tough position to take when my son disputes it.