[grey-area]

Bitcoin is not 'electronic cash' as you define it here - it's a shared ledger - there are no coins. The only difference with a current account at your bank is central ledger vs distributed consensus ledger.

Also why would a bank require physical cash? Banking is based on savings and loans, debt and credit, not cash. The money in your bank account is not backed by real coins somewhere in a vault.

[chrisco255]

There's a big difference. The bank is able to create money from thin air when you deposit funds, thanks to fractional reserve banking. Banks typically only need to hold 10% (or less) of total funds deposited. The rest they loan out, which always finds its way back into the banking system, so that effectively, banks are able to loan out about 10x what their depositors have in their accounts.

Holding Bitcoin, on the other hand, is more like gold in that there is only so much of it.

[grey-area]

The amount of bitcoin on the ledger is increasing all the time, it has not reached the limit yet. This is also defined by software rules which can be changed.