I think you have to have a loose grasp on many concepts to even ask this question.
Do Post Offices use more energy than an email server? Do bicycle messengers sweat more than fax machines?
In the USA, Post Offices are being closed in favor of parcel services. Many towns don't have them anymore. Besides, you can't email Grandma's cookies, but you can email and sign a contract. I didn't know bicycle messengers could deliver messages overseas, or was that a strawman?
Post offices almost certainly use many time the energy (and cost even more to operate) then email servers. If you are looking to reduce our overall energy footprint it would probably be best to close many/most post offices in favor of using email more and using reduced post office 'foot print' in favor of shipping parcels (packages)
Not a fan of banks. But you will have to agree that banks do a lot more than money transfers.
It would be more accurate to compare Bitcoin to Western Union locations...
Banks don't do anything that can't be done by a machine.
[/quote]To make an accurate comparison you would need to measure the amount held by banks, the amount transferred by banks, the amount transferred by places like WU, and the total energy consumption of all banks and MSBs like WU. You would then compare the amounts transacted with bitcoin (actual economical transactions) and the market cap of bitcoin with the energy consumption of ASICs and the energy consumption required to keep private keys safe