Just as an example, Bank of America has over $2 trillion in deposits. If any minimally significant portion of that amount goes missing, it's pretty easy to track just due to scale. There are policies in place that ensure any transaction above a certain size gets looked at. If there are too many large transactions in a day, that gets investigated too. In exchange for having these safeguards in place, the government is willing to guarantee these deposits in the form of FDIC insurance.
Banking regulation is a good thing, especially when you're talking about an anonymous currency where transactions can't be rolled back.
EDIT: Just wanted to add that while Bitcoin itself probably will never be a globally significant currency, some form of cryptocurrency is likely to obtain relevance. But some people are going to get burned along the way, and these are the risks that you need to accept if you want to dabble in what amounts to unregulated banking. The regulations exist for a reason.
My uninformed intuition tells me it's more likely that there will be a Gold and a Silver - one better, one worse, each used for different things.
It's basically like carrying cash: you can walk around with $10,000 in your pocket, but if someone robs you and gets away, you're out $10,000. If someone steals your credit card, the bank has fraud protection measures in place that limit their losses, and they often can roll back transactions. Unless you impose a similarly regulated structure on top of Bitcoin (where banks are super-secure and won't transfer large amounts of BTC without an auditable authorization chain so people become personally liable for any fraud that may occur) you're not going to be able to solve these problems.
Deflation is a bigger issue, in my mind. The algorithmic scaling of Bitcoin basically ensures that it will either not be very much in demand at all, or it will become increasingly scarce relative to demand over time. This creates an incentive to buy and hold Bitcoin as its value has tended to go up over time. However, most of the modern economy is based on the assumption that money today is worth slightly more than money tomorrow. This creates pressure to spend or invest, rather than hold onto currency for any reason other than liquidity. If Bitcoin remains popular, it won't be because of its virtues as a currency.
Plus there is that whole thing of regulations about bank responsibilities.
(I am not a banker.)
According to the FDIC, for most banks theft is covered by the banks insurance policy (they refer to it as a "banker's blanket bond") which also covers loss (of money) by fire, flood, and even things like embezzlement etc.
So until BTC exchanges/etc actually have insurance policies (literal policies, not figurative "insurance policies") the risk seems higher.
Also worth considering - I remember reading about a bit coin site that uses a Safe Deposit Box to store the majority of its holding "offline", but safe deposit boxes aren't insured by either FDIC (even in the event of bank failure) or by the bank, so if their safe deposit box is breached (either as a theft or just damage) there is no safety net.
What exactly is a hot wallet/storage?
A cold wallet is one where the keys are kept offline and not plugged into anything, eg, a printout, or a USB key.
Bitcoin developers haven't quite cottoned onto the wisdom of separating these functions architecturally. (One of many advantages is "If your matching system is compromised, you shut it down and investigate, but no money actually leaves. The settlement system is in your back office and much more protected than the matching system, because the settlement system doesn't have to talk to customers directly.")
Bitcoin developers instead have developed a security pattern called hot wallet/cold wallet, where BTC which are available to the system are "hot" and BTC which are not available to the system are "cold." The idea is that, in any given day, you might only require 2% or so of your company's total reserves to go in or out. You keep the private keys to, say, 5% of it on the live system. That's your hot wallet. You keep the private keys to the remaining 95% somewhere else. That's your cold wallet. Even if your live system is rooted, you should not (the thinking goes) lose the private keys to the cold wallet.
The Bitcoin community widely believes that this pattern is sufficient to prevent events like the recent Mt. Gox debacle, where the system was compromised and both the hot wallet and cold wallet were drained.
Doesn't that violate the real time nature of bitcoin then? I have built e-commerce settlement systems in the past and I thought that the big challenge with bitcoin was always the instantaneous element.
BTW: Bitcoin isn't a real-time system. The community widely believes it is, but people who actually understand what is happening would say "cough Yeah by 'real-time' we mean 'an hour later' cough."
I'm not sure this is true. Any off blockchain transaction is basically an unsettled (and therefore reversible) bitcoin transaction. So for example, trades on bitcoin exchanges and payments between web wallets will have separate and distinct settlement phases. Generally bitcoin enthusiasts gloss over this though, because they don't like the idea of reversible transactions.
The current maximum transaction rate for the bitcoin networks is something like seven transactions per second. So either they'll have to figure out how to increase that or move to a more conventional clearing and settlement system if bitcoin-as-a-payment-network ever takes off in real size.
What? I'm not entirely sure that I understand this correctly: Do you say that the whole bitcoin network, with all that computing power, can't compute more than 7 transactions per second?
See here: https://en.bitcoin.it/wiki/Scalability
Altcoins which have chosen blocktimes of say 1 minute will be able to do more transactions per second, and ones which lift the 1MB cap likewise.
Are you saying that Bitcoin-based financial systems cannot introduce a more secure settlement system without fundamental architectural changes to the Bitcoin protocol?
Or are you simply saying that nobody has apparently done so?
If the former, I would like to challenge that assumption. If the latter - what are you really trying to get at?