I don't think it's going to be a list of things, but rather a list of vendor types (grocery stores, pharmacies, gas stations) that have to accept offline paymen

I don't think it's going to be a list of things, but rather a list of vendor types (grocery stores, pharmacies, gas stations) that have to accept offline payments, and that banks must accept offline payments from. You can live without a new iPhone if the terminal is down, but you can't live without food.