Crypto coin is the next best thing to cash, I would say that it's in the bag if you use a wallet on your phone, although it could be argued.

sure if you don't mind waiting around anywhere from 15 minutes to an hour for a transaction to be confirmed you can replace cash. sure if you don't mind your every transaction being published on a immutable public ledger and linked to your wallet. don't get me wrong it has its place and use but its not anonymous or quick cash is both