No they are saying they don't need a decentralized public blockchain because they can't control it which is well the whole point of it.
They're giving funny excuses like:
Hence, proof-of-work-based blockchains like bitcoin offer no way to predict their future security level, or settlement, since it is directly proportional to the tokens future value, which is not knowable.
which is an interesting point about bitcoin, but is also laughable because one can say the same of the US dollar. It's a token whose future value is not knowable. We'd like to believe it's a stable store of value, but the Federal Reserve and US Treasury are the counterfeiters of the global reserve currency. They can devalue at any time.
I actually think he has a semi-valid point here. Let's take the Bitcoin blockchain.
He's saying that right now, using Bitcoin's blockchain to settle would probably be fine. There's enough mining power to keep the network secure against double-spends/reorgs. Within a reasonable amount of time (for instance, the standard six blocks), a transaction could be considered settled.
What he's concerned about is future-proofing. We can say that today, Bitcoin is fine. But what if, in five years, Bitcoin's price has plummeted back down to $4.25? With an extremely low price, the network couldn't sustain its present hashrate, since hashrate is ultimately dependent on the reward (in fiat terms, since that's how electricity bills are paid). If the reward drops dramatically (in fiat terms) because the value of the token (in our example, Bitcoin) has dropped, then the blockchain is no longer nearly as secure.
Bitcoin, in fact, is an excellent example. Right now, Bitcoin's hashrate is 1,220,000 GH/s. What if the price of Bitcoin drops from $425.00 to $4.25? Presumably the hashrate would decline about 100 fold, down to 12,200 GH/s. The thing about a scenario like this, is that people are unlikely to simply throw their ASICs in the trash. Most people will probably turn them off and keep them in storage somewhere, just in case.
Now let's say that Chase bank uses the Bitcoin blockchain to settle a $100,000,000 transaction. Somebody who's sitting on the sidelines could suddenly turn all their miners back on and use their hashpower to orchestrate a blockchain reorg which would effectively reverse Chase's massive transaction.
So he's right--the security of a blockchain depends on the value of the token.
My question is whether Dash is different due to its masternode network? Particularly in Evo, where all transactions will (presumably) be IX?Possibly. I think you're right here, that in fact the MN network with POW and quorums settling/locking transactions makes Dash far safer than POW alone.