How is it not an issue? My ability to pay should not rely on my phone's OS and payment app functioning correctly. It should not rely on me having remembered to

How is it not an issue? My ability to pay should not rely on my phone's OS and payment app functioning correctly. It should not rely on me having remembered to charge my phone. All of these phone payment systems go through the credit card companies anyway. Printing out the plastic card is not the main service they provide.