No, not “that one coin”. The whole blockchain. Thousands of different cryptocurrencies and smart contracts are secured by it. The whole network is holding tens of billions of dollars worth of value, and it takes an estimated 8M USD worth of electricity in a whole year to secure it. There is no way that any existing financial banking system will ever be as efficient as this.
Arguing based on “how long it took to get there” is at best just bad argument based on sunk-cost fallacy and at worst moving the goalposts. If you care about “irreversible harm” from CO2, it would be a lot more productive if you wrote to your local city council to abolish parking minimum requirements than hating on a project that from the start was focused on creating a consensus system that did not require PoW.