It has been a long time since I've heard about "buy now pay later". We have some form of it left in the Philippines, with credit card companies. You buy something with card, and you delay the payment of it next month, and can even be split up with zero interest. I don't think BNPL companies that you mentioned would last long unless they change how they operate. In the US, I think it is easier to declare for bankruptcy so those BNPL companies are taking huge risks.
They are taking risks, but they are taking it on the back of society. They might fail, but what they are doing is a cost to everyone else, as when people file for bankruptcy, they aren't left to die in the street.