As some point out this is based on the price of buying hashing power from NiceHash, which in case of Ethereum can at most cover 7% of Ethereums hashing power. A

As some point out this is based on the price of buying hashing power from NiceHash, which in case of Ethereum can at most cover 7% of Ethereums hashing power. And costs are different if you need to buy/invest in the hardware to pull a 51% attack furthermore even if you "could just rent more" you would be adding hashing power to the Ethereum network increasing when 51% is hit as you don't replace hashing power, and then the more you buy the more "pricey" hashing power becomes... that is if you can even get the required amount of hashing power in current economics. (E.g. if Etherums current hashing power is 100 then you need >50 hashing power, but you need to get >50 hashing power OF that 100 hashing power if you just add 50 hashing power you now have a total hashing power of 150 and as such need 75. So if you control 0 of the current hashing power and have no way to reduce that you need to add >100% of the hashing power to controll >50% of the final hashing power...). The 51% attacks only allow double spend attacks, you can't "steal" money and the attacks sooner or later will be noticed and might be reversed. Then even if you run a 51% attack it's still a crime in more or less any country and controlling 51% of hashing power and staying truly anonymous isn't easy, given how much electricity and hardware PoW consumes. (But it's viable, through maybe only if you are state backed.) The most feasible way to pull of a 51% attack on a larger network IMHO is by hacking multiple hashing pools. Through like the article mentions it's a completely different thing for smaller networks. It also shows nicely why you need increasingly more hashing power the more value moves through your network (it's a counter argument to people defending PoW by saying you could just do more transactions per block). It's also why some new chains which use PoS start out with "a farming game" where people already "stack" money before the crypto currency is worth any money (and get money based on that when "it goes live"). Because with that you can start with a already reasonable secure system. > I'm not able parse what it tries to say. 1. Small crypto currencies are not so secure (if not build on another chain). 2. PoW is not as grate as some people make it out to be (IMHO PoW a terribly solution but it probably was the best terrible solution when Bitcoin was made). 3. And I would add: PoW based Currencies hashing cost and marked value needs to be in balance. (For PoS it's the stacked amount and marked value, which is IMHO easier to archive as it doesn't require additional factors like access to hardware and cheap electricity.)