a coffee shop would not care about confirmations, tansactions are instant, only confirmations take time,

but more importantly, businesses would simply work a number in to their business model for any bad transactions, as beleive it or not, the majority of people are honest.

So it only fraudsters that would need to worry, which a camera takes care of,
when paying in person the exact time will be recorded, and would not take long to be detected

it would be so much more risk of getting caught than say using a credit card or cheque for fraud.