At first sight it may be useless (in this form anyway) but I've read that people tend to spend more by having credit cards because you don't have a physical reminder of how much money you have left, it is just a digital number. I'm predicting that in the future we will have solutions to bring back some physical stimuli to our digital transactions.
See also: http://www.dailymail.co.uk/sciencetech/article-1336164/Smart...