I think it's inherently cumbersome. The traditional banking system has really bankstrong safeguards against this sort of thing. A technical glitch can't just make millions of dollars disappear - if there's a glitch the bank and/or the authorities step in and reconstruct what the actual balances should be.

Keeping Bitcoin requires you to be really good at both storing a specific string of bits, and also keeping that string of bits secret. Even for a really skilled sysadmin, trusting your life's savings to your own ability to secure and back up a single string doesn't strike me as very wise - compromise or misplacement of digital secrets is almost inevitable.