Because transactions between virtual accounts do not happen on the blockchain, they do not incur blockchain transaction fees and are happen instantly. This provides huge benefits for working with blockchains like Ethereum and Bitcoin, both of which have high transaction fees and slow transaction times. Virtual accounts allow you to build solutions parallel to the blockchain and bypass the slow and often congested transaction mechanism of the blockchain itself. If users want to send their crypto outside of your app, they can withdraw it from their virtual account to their blockchain deposit addresses.