Just to elaborate here. You are describing one implementation of a blockchain that provides a cryptocurrency. Blockchain is literally just another form of a database. It’s just that it can contain traits that would allow the database to be shared and distributed unlike typical databases. Currently there are some companies that are utilizing blockchain for their inventory systems. They aren’t using any more energy than they would with a typical system. They are just doing it to keep an unchanging record of past transactions which helps with fraud and loss prevention.

P.S. Money laundering using a system that is publicly distributed and has every transaction involving usd paired with an ID, social security number and enough pictures of your face to make a 3D model is genuinely idiotic.