Crypto's volatility in price greatly defeats its purpose as "digital cash". Until this issue is solved, I don't see the possibility of living without a bank.
This is due to the fact that cryptocurrency's value is still measured with reference to Fiats, for it to be used as a valid means of transacting it has to have a value hedged on labour; wages/hour, properties etc. So, 1
BTC would always be equal to 1
BTC.
This would provide stability, but it's not practical at the moment due to low adoption levels, and also the dilemma of which cryptocurrency can provide transaction security, decentralization as is scalable.