The money can be used at any food supermarket , grocery store etc. So it is a card. You can't use it to pay rent. You can't use it to give your child allowance money. You can only use it for food, clothing stores 4x a year maybe which is generous (4 seasons).
So you can buy your child toiletries, food and clothing. And maybe allow the mother to write checks off the account for certified expenses like private school tuition fees. The legislators can make sure all schools are equipped to accept the CS card as needed as a form of payment.
as a national program, it won't ever be accepted. it's intrusive and costly to even try to enforce.
on an individual level, only using it for clothing four times a year? can't use it towards bills? as many have stated, a part of rearing a child involves shelter, electricity, water (washing their clothes). can i buy junior's plane ticket with it? can i put gas in the car because i drive them to school and that's completely out of the way for work? what about their extracurricular activities, can we pay the karate teacher with this card?
it's a babysitting program suggested because people suspect that they can't/shouldn't trust the mother (or father) of their child. if there were things that this card didn't cover, but were still for the child, many noncustodial parents wouldn't help make the difference up because they already pay child support. but the money would be inaccessible