Honestly, once it reaches critical mass. It will mean the end of PayPal, Venmo et al AND the credit card industry as a whole.

I doubt it will hit the credit card industry that much. We have something like this in Canada, Interac, and credit cards are alive and well. They may actually prefer this, because people who keep zero balances may be less inclined to use credit cards instead of debit cards and there may be a larger market of businesses with card-processing capability to cater to those who have debit cards but don’t have the credit to obtain credit cards.