A centralized alternative to Bitcoin would be a simple SQL database with a schema representing standard double-entry accounting and some meta-data fields. The entire transaction volume of the Bitcoin network could be handled by a Raspberry Pi in a shoebox.
Instead, we have a transaction volume of a few hundred thousand database entries a day being handled by a compute cluster comparable to those used to simulate atomic bomb blasts with physically realistic voxel models or probabilistically describe a complete relationship graph for the human proteome.
He's right. Read that article. Distributed trust is hard. The problem isn't trust, though; it's easy identity creation.
Any voting system will fail if someone can cheaply and easily create new voting identities. Email spam, web spam, and social networking spam all suffer from that problem - email addresses, web sites, and social networking accounts are cheap and easy to create. Bitcoin beats this by giving voting power to whomever spends the most on mining hardware. That works, but at high cost and only because there's a big financial reward for being a big miner.
How to limit fake online identity creation? Facebook tried "real names", which semi-worked until they ran into the gay agenda. Google tries to make you tie your whole life into one account, and they can tell if your account doesn't have enough of your life tied in. The credit industry tries to do this by chasing down people who don't pay up, and is reasonably successful, but at high cost.
ID by phone number has been tried, as "phone verification". That created a small industry in phony phone numbers. (http://www.sitetruth.com/doc/socialisbadforsearch09.pdf) ID by postal address was tried, but there are too many mailbox services.
If you want a centralized system, just use your bank, Paypal or whatever. Nobody was claiming that Bitcoin, a distributed system, was more efficient computing than other systems. The whole point of Bitcoin is that nobody controls it. Finding something that is more efficient than Bitcoin, without the decentralization, is plain stupid. I don't need an "expert" telling me that "hurr I could have done that faster with a SQL database".
I agree that stellar-like systems might have a role to play in the future, but surely a coin with an incident of corrupted transaction logs is inferior to one without such an incident, all else being equal.
EDIT:
To those pointing out the 2013 Bitcoin fork, good point.
However, in cryptocurrency land, 2013 is ancient history, and I'd argue standards are higher already.
Equating the specialized computation approach to bitcoin's mining as being necessary for decentralized consensus is ridiculous, it is just the path bitcoin chose. Mining algorithms that depend much more on large and fast memory could just as easily work.
Also, the benefits of decentralized consensus has benefits the are so vast, the resources it takes to achieve it are miniscule by comparison.
I particularly enjoy this quote from http://adamierymenko.com/decentralization-i-want-to-believe/:
A centralized alternative to Bitcoin would be a simple SQL database with a schema representing standard double-entry accounting and some meta-data fields. The entire transaction volume of the Bitcoin network could be handled by a Raspberry Pi in a shoebox.
Instead, we have a transaction volume of a few hundred thousand database entries a day being handled by a compute cluster comparable to those used to simulate atomic bomb blasts with physically realistic voxel models or probabilistically describe a complete relationship graph for the human proteome.