Currency, except for small change, will disappear. Your wealth will be recorded in zeros and ones of electronic data, as so much of it is now. It is as if all people use credit cards but the transfer of credits is instantaneous. Income tax forms disappear, your tax is automatically computed from the record of debits and credits, as well as other data connected to your file. The system of electronic currency will never be acceptable unless the laws protecting privacy are greatly strengthened.
Cash facilitates anonymous transactions that people are unlikely to give up.
So laws regarding crimes like gambling and prostitution must be reexamined. Implementing electronic currency will in itself be interesting. The government will have to be very forgiving of the rural person who trusted the mattress more than the bank. But a huge amount of illegally obtained cash will never be turned in. Clearly we'll need electronic backups and protection.