You can always use a credit card as a debit card. Pay it off to zero every day. Indeed with the very low limit cards people with bad credit can get, you kind of have to pay it down faster than the bill comes if you want to keep using it.

With cash you can't overcommit - you can only spend what you have - with card you can. If you are poor, overcommitting is very tempting as otherwise you will be going without things you need/want. But that temptation leads to debt.

True, cash is good if you lack discipline. For such a person, more flexibility leads to less because they misuse it in a way that reduces flexibility. It's a footgun for these people.