Safe or not it depends on how we use it, so digital money and paper money are just the same. Both have the potential to disappear, so we must be careful using it. If talking about the future maybe yes it is a digital concept, but in my opinion does not mean paper money will be abandoned. Indeed, the circulation of paper money will be reduced but in some direct transactions I still believe the paper money will still be used. For 10 years from now I'm sure the paper money will still have a big demand.