Sort:  

PoW is also proof of environmental pollution, power wasting and unsustainability ;) Ok, as you see, I´m not a huge fan of PoW coins and avoid them in my portfolio. There is a reason in my opinion, why all 3rd Gen coins rely on DPoS or similar concepts - it´s also a matter of scalability and to keep things in a smaller frame: people want to be part of and active in a blockchain, to identify themselves with a project. Most people simply can´t afford PoW, but can (like Steemits "proof of brain") offer other resources in a much better and more human way. Just my 0.02 SBD on this topic :)