Let's say all usability problems were solved. I'm imagining something like shops with tills that present QR codes for the amount and payment address for a transaction, and mobile clients exist that can scan them and present and easy Pay / Do Not Pay choice. So paying in a shop by Bitcoin would be no harder than credit/debit card, or even cash.
What limitations inherent in the Bitcoin protocol and network might prevent this from working? I'm thinking of things like:
- Network latency (transaction being received by the shop) holding up queues
- Poor mobile reception meaning shoppers find they unpredictably can't send money
- Lack of confirmations before the customer leaves meaning shops may sometimes lose payment
I can see this being less of an issue in slower transactions, eg pubs, bars, restaurants. Are the above problems likely to materialise, and if so, are there any other types of transaction that might be affected?