The use cases that he sites include buying an e-book using a smart contract or its use in the supply chain or voting. The e-book example is slightly misguided, because this is not an use case where decentralization provides much value. So the entire discussion about auditing smart contracts is rather unnecessary. But it is nonetheless an important objection that may become important in DAOs. But it's short sighted to think that this problem won't be solved. Some companies are already starting to tackle the smart contract to natural language translations (e.g. Iolite).
Supply chain is yet another use case where it is unclear whether blockchains will add value. Perhaps cost saving. But note that the blockchains used in supply chains will most likely be private, therefore permissioned. It's unfair to put private and public blockchains in the same basket, because they are very different beasts.
Finally the use case of voting. The author thinks that whoever is in power might distribute a few additional addresses to their cronies to manipulate the system. He is missing the point that all data is public in public blockchains. So anyone can audit the voting results later if they want and discover that those addresses do not belong to any real people (assuming there is a KYC type identification system built-in). Voting is an use case where blockchains are sorely required. All we need is for the knowledge to reach public consciousness and for the people to tell their governments that they want it.