There are still many parts of the world, including stores, taxis, but also people with smartphones, that do not have Internet. It is doubtful that even in the long-term future everyone is going to have internet on their smartphone. So how is bitcoin going to work for retail transactions? Imagine a store without public wifi. Can transactions be processed if only the vendor has Wifi?
Credit cards can work on either a phone line or internet, so it would be ubiquitous as opposed to bitcoin which cannot work on a phone line?
Internet connection is still a problem to some countries specifically in some certain areas in some countries. Though everyone has a smartphone, not every area in their place have internet connection. Public places in some other countries still have no free internet to its people and that is one of the major reason why stores don't go fully digitalized because of the access to the internet. And it is also the reason why some people are still not familiar with bitcoin and other cryptocurrencies.