SilkRoad was important, but most important was its community (dkn255hz262ypmii.onion) that it's still online. You see, the most important things for the anonymous market are the WoT and the PGP pubkeys, and that's not illegal (at least until now). Additionally Black Market Reloaded was already very popular when SR was seized.

I believe that what is pushing Bitcoins value is that many people call it "the credit card of the 21st century" and they are buying bitcoins as shares of the next Visa.

EDIT: as wildgift said, there is no insurance in Bitcoin yet, but I'm sure that if Bitcoin starts being really popular we are going to start seeing online wallets with insurance provided by big corporations. CCs (as a technology) don't include insurance either...