Explain how PoW 'wastes' energy, if it is not sustainable to use high demand energy to mine. Miners who use 'free' or cheap energy, indicating low demand, will always out compete those attempting to use retail energy to fuel mining. Excess and stranded energy are the only sensible, sustainable sources for hashrate based mining. I use 'sustainable' in the context of mining operations, not globally or abstractly.
Efficiency is the ratio between what you spend, and the useful output you obtain.
The output we want from a blockchain is capacity to do work, that is transactions.
PoW means you're burning more and more energy, while the amount of work the network remains constant, because none of that energy actually results in more useful work being done. Thus the efficiency of PoW chains goes down and down and down.
Well its my personal opinion that washing machines are useless, so obviously they do nothing but waste energy. Please level up your argument and put a bit of effort into good faith.
No part of his response is opinion. Proof of work adjusts the difficulty of mining (literally search "proof of work difficulty") so that the number of transactions processed in any unit of time is roughly constant regardless of the amount of energy going into the system. Transactions processed are useful work. The energy going in does not increase the amount of work produced. This is why crypto holds value (if you believe in it): a finite amount of reward is produced per unit of time, but the material cost of producing that reward increases over time as the system expands. You need to spend more resources to mine more cryptocurrency because the algorithm makes it less likely for you to be rewarded as more people do more mining.
Correspondingly, if I buy a washing machine, I can do one load of laundry per hour. If I buy a second, I can do two loads per hour at the expense of more water and electricity. If washing machines were powered by proof of work, adding more washers and using more water and power wouldn't increase the number of loads I can wash per hour. The algorithm would see that too many loads are being done per hour and decrease the efficiency of each washer to compensate.
