A problem with an untraceable currency is that it's also very easy for an exchange to collaborate with a hacker and vanish (or declare banckrupcy). Not saying that is what happened here, but that would be my fear.
And insuring bitcoins has its own logistical challenges that will probably scare an actuary.
Trust is a hard one as I'm sure the people who used bitfloor had trusted it until today.
A digression: Bitcoin would be the government regulator's wet dream if you could assign people addresses (and they could only use the assigned address), because you can trivially track all transactions. Actually, I have in mind a way to implement such a system in a (likely) cryptographically sound and enforceable way. But in theory, the government could outlaw cash and track all transactions anyway.