Base on my reseach ,and my own idea .. I think Sweden is the one of the richest countries in the world and their citizens are already using mostly electronic transactions, this is in contrast to Japan that despite being one of the most advanced countries of the world most of its transactions are still on cash, so it is a matter not only of wealth but of culture, to be honest I think it is a terrible idea to eliminate cash, if electricity goes off in a significant part of the country for some days their citizens are going to go hungry without cash...