I mean let's face it, it's easier to handle money electronically than with papers in the hand. And if we compare fiat on the bank account and the blockchain money guesses who have the advantage...well not quite yet, but the potential for the blockchain is huge.
The advantage of electronic money is the major reason that bitcoin and digital currency have not been dismissed or jettison. The usage of electronic money helps in the understanding, usage and near adoption of cryptocurrency. It would have been a total failure if there was nothing like electronic money in the first place. This is why we still hear of bitcoin and altcoins, otherwise, it would have been long forgotten to the anals of history.
You using your debit card and transferring money for beer to a friend using Venmo isn't the same the same as "digital cash" though.. For one thing you have to trust a third party to be able to verify your funds. Using cash you can verify someone paid you and that you have the money by looking down in your hand and seeing that you are physically holding cash.
The great part about Bitcoin is that it has both the benefits of being digital and also having no third party needed to verify that you are holding cash in your "wallet".