here's the problem with a rollback: You sell me 100 oz. of GOLD, not fiat, not bitcoin, not pork bellies (tho the pork bellies wld be same as Au) for an equivalent amount of VRC.
You and I agree that VRC has value, so we agree to the exchange, I send you VRC, you ship me gold coins.
A bad man steals many VRC from MintPal. Blockchain gets rolled back. I get my VRC back.
*But I Still Have Your Gold.*
No. When you get the money from the rollback then you pay the guy who sold you the gold. Unless you want a broken knee cap.