And each transaction gets to burn the equivalent of 10 gallons of gasoline instead of an atomic logged database transaction (which could even be published and cryptographically signed cheaply).
It will certainly be better with Proof of Stake & sharding, but I was curious how bad it is today, so I looked it up. One ETH transaction consumes 86.94 kWh of energy. Wikipedia says gasoline has 8.83 kWh/l energy content, so it looks like about 10L of gasoline per transaction (not 10gal). Still, there are about 3.8L/gal, so if you factor in that heat engines are about 25% efficient, then you are right. What a crazy world we live in.
