franky1, you still make assumptions that are false. Bank don't need to use computers to create currencies. And, they are not controling anything... just ask to those who crashed in the pink papers and mortgage scandals...
how any atm is working out there? how they can have all those transactions per day, they are obviously using tons of power
you can argue that this power may be partially free due to the usage of a massive panels farm to have solar energy or any other green energy, but this cna be done with bitcoin too