Why does it have to be limited to smartphones? What prevents a system similar to M-Pesa built around a cell service provider offering a BitPay like service? Does anyone here have direct experience with M-Pesa?
My only issue is that the application platform is so widely adopted that this may take more time than is efficient to establish. It would of course open the market to everyone with a phone, but everyone wants a smartphone.
Coinvestor (Ryan)
Well, many more non-smart cellphones exist, and I had a $9 phone that worked quite well before buying an Android. I got the smartphone for the other apps, not for the possibility of using it to spend bitcoins. Not everyone is going to switch for many years, most people just need a phone and maybe SMS texting. Even my $9 phone could securely connect and use my account balance with the service provider.