You’re right about the environmental footprint - proof of stake dropped the energy consumption by 99.95%
Ether (ETH) was never intended to serve as a digital currency. it was only meant to be the fuel or incentive for computational tasks on the Ethereum network. An L2 like Optimism or Arbitrum runs on top of Ethereum and facilitates transactions that are significantly faster (tens of thousands of transactions per second), for a fraction of the cost (pennies or fractions of pennies)
So how does that work, is the 300psi rating calculated by the difference between internal and ambient pressure? Does it not matter whether the greater pressure is internal or external?