If you are buying coffee who cares about confirmations at all? Once the product is in your hand you are done.
It's the seller that would care about confirmations in that case. Hopefully they do something hilarious like have a bitcoin corral for people to wait in while their payments clear.
My point is that such a limited amount of money is at stake that confirmations really aren't all that important in this example. I think most places would just accept the risk. Heck, they could have the POS alert the owners if anything fishy happens between payment time, and when you actually receive your drink if they are really concerned.
I really don't think this is as big of a problem as you are making it out to be.
I don't think I'm making it out to be a big problem, I was just pointing out that for small transactions involving physical goods, the recipient of the digital currency is the one that is going to care more about the transaction finishing.
People still wait for coffee? I order from the app; it's paid for and ready for me when I walk in the door. With a 3 minute confirmation time, this flow still works. If it doesn't confirm, then they corral me, I guess.
It's the seller that would care about confirmations in that case. Hopefully they do something hilarious like have a bitcoin corral for people to wait in while their payments clear.