“Bitcoin is the only system which solves this problem at scale without a trusted third party, and energy usage is the key component of that solution.”
When Bitcoin maximalists say things like this they tend to forget about all the other cryptocurrencies out there.
And this part isn’t true (think of all the proof of stake coins out there). Nano provides finality and decentralization with no fees and the proof of work required for their system is extremely tiny compared to bitcoin. The challenge with Nano is that a currency that is free to transact is easily spammed, but the latest round of countermeasures being deployed in Nano should render spam attacks ineffective. (Look up “Time as a Currency/P4Q” on Nano forums if curious.)