As a tangent, would you consider biometric identification (in the broad sense - retina, finger print, DNA) a priori identification as well?

I'd argue that one thing would make payments more seamless: identity = payment, in other words, you don't need a middleman (e.g. credit card, chip and pin, or mobile device) to verify your identity. You just show up and pay. No more carrying anything around. Think: Minority Report. That would possibly take decades and involve many privacy concerns from citizens.

Meanwhile, you'd have the same security risks you had before, playing the cat-and-mouse games with hackers (of all types, including biometric hackers).