Proof of work was the original mining method by which cryptocurrency transactions were processed. It grew out of email anti-spam control measures, and is central to Bitcoin's transaction process by which transactions are added to the public ledger.
Proof of work is expensive and the equipment eats up electricity. Since most electricity comes from coal-burning power plants, it hurts the environment.
As Ethereum 2.0 emerges, which will transition Ethereum from proof of work to proof of stake, even more cryptocurrencies will take this route. Instead of buying expensive mining equipment that is noisy, produces heat and gobbles up electricity, one can focus on holding the coins themselves.
Proof of stake is energy efficient, lucrative and allows the miner and holder to earn consistently. There are different modes of proof of stake that reward the holder, and this will become the future of cryptocurrency transaction processing going forward.
Picture from Pixabay.