k good things...the hacking, or inside jobs, or open sourced are serious concerns. Even today with our current banking system there is hacking, inside jobs, fraud, etc..blockchain actually is more solid than what we have. The problem with bitcoin (including the mt gox.) is that if your keys are not secure, you stand to lose everything. Think, it's strongest point is also its greatest weakness...risky. bitcoin is 100% secure until you keys get into the wrong hands. Bitcoin is too big of a liability to serve as a world currency, too many people are trying to steal, and this would be too easy for them (if everyone were a target) the most people, will not accept it to be a serious store of value.
For the bitcoin mining, it will end someday. Mining pays less and less per block, someday it will be a losing propsition. There will need to be bigger fees per transaction paid to 'miners' to in order to keep break even. Still these fees will not be much. With some gold backed blockchain there won't be 'miners' because this blockchain is backed by real gold, and we can't just crypto real gold into the vault...so each transaction will be a tiny fee too. It will be a reward for contriubting. There will be so much transactions that this will be such a tiny ammount, equal to 1 penny or less per transaction. Our old system of money costs more to process.
If governments did launch a blockchain gold backed currency, you probably wouldn't have the keys, unlike bitcoin. it would be a private blockchain, where you were assigned addresses, but they controlled the 'wallet'. This means u are trusting your life savings to them, but aren't we already trusting our life savings to banks? If the government will have many contingency to deal with problems, also they have so much resource they can catch the person, they will make harsh example of anyone trying to steal. Also, if anyone did get 'hacked', nothing of real value is being stolen, because the gold is locked up in the vault. This is why it could be better than Bitcoin. With bitcoin, someone can keylog or otherwise hack your computer and steal all your bitcoin, your life savings. No one will help you, and you will be completely screwed. This is why bitcoin will not be adopted mainstream. With a private gold-backed blockchain, the governments and banks have a vested interest in protecting your money. They can trace any theft on the blockchain no matter how complicated the route, and probably fix the problem. There are scammers everywhere, scamming everything, all the time right now! blockchain, a rather centralized and universal system will make it so hard for the scammers comparatively.
Most people resent the ideas im saying. They think blockchain is the bee knees and it is ment to cut all the government and banks out. I think above that I proved why that won't happen. There is happy medium though. The ledger can still be public, we can see every transaction too, no funny business between polititions, banks etc.