Errors:

0:40 - "witness are under control of the shareholders". Incorrect. They can do whatever they want until they are replaced by an election.
0:45 - "actually more secure than Bitcoin". Incorrect. I explain why in my white paper.
0:48 - "proof-of-work is ... burn most money is most secure ... proof-of-stake ... is also a scarce resource". Incorrect.
1:40 - "all systems are vulnerable to 51% attack ... no such thing as avoiding 51% attack". Incorrect. PoS is economically vulnerable to double-spends, Bitcoin is not. I explain this in my white paper. Correct that all systems have some form of 51% attack, but PoS has additional 51% attack vectors.
2:10 - "where we get the advantage over proof-of-work is that the cost of acquiring the 51% is much higher in proof-of-stake". Incorrect. Much easier to borrow or rent 51% stake than to rent 51% of mining farms. The mining farms have too much at stake. The shareholders have nearly nothing-at-stake because of their shares being an undersupplied public good. Worse yet, it may be more profitable for the whales to double-spend and short, than to sell their stake straight up.
2:20 - "because DPoS uses deterministic manner of producing blocks, we don't have to rely on random chance". Incorrect. He fundamentally does not understand resiliency and liveness. I explain this in detail in my white paper. Thus he doesn't understand why Graphene will never scale up to the world. Dunning-Kruger-esque.
3:30 - "get non-linear growth in the ability to achieve things when you concentrate capital". Incorrect. He is touting the concentration of nodes to 110 witnesses as being some advantage, because he never figured out how to otherwise solve the propagation scaling issue that plagues an unbounded number of nodes. But it doesn't follow that a concentration, bounded, and permissioned, provides resiliency and liveness. He is conflating.