But you slow down to a crawl if you are iding every customer, they might be using false ids or they've moved since the last time they got a license etc. Plus if you've ever saw a cops episode it seems everyone walks/drives around without any id (maybe that is just criminals some how thinking that if the cops can't figure out who they are they'll just let them go :)). The US is the only rich country I know of that still takes imprints (been to France, Germany, Czech, UK, Belgium, Italy, Netherlands, and live in Canada). I've actually never had a imprint of my card because we've always had electronic readers and for the last 5 years or so chips in the card. I don't even know how many stores still have the ability I think it has been over a year since I even saw a imprint device.
I think it will end up being like when traveling to another country with a developed banking system for a long while: you'll pay for almost everything with credit cards or a head of time but you'll still have a couple hundred (equivalent) around just in case someone won't take it for whatever reason.