Here we go again, and the Vault issues certificates as a receipt for said BTC's right.
Because Bitcoin is entirely digital, this might offer the possibility of organized bank runs to keep the banks honest.
or least we would expect real-time auditing ... running totals of total BTC on account and total claims on thse funds ... no reason not to and if BTC addresses are supplied it could be publically auditable by third party.
... modern banks would hate a hard currency cause they can't just paper over the leaky cracks they live off for free. They have to go back to being vaults and nothing else. Financiers on the other hand may get a new lease on life, true entrepreneurs and risk takers.