You make it sound as if it is reasonable for a transaction is to cost 2kWh, that is a huge amount of electricity/energy. If anything that used that much energy became the dominant means of payment, the average person would use more energy in payments than they would in powering their home in a day.

Trip to the shops, but fuel, some take away and a few things online when you get home and you’ve used 10-16 kWh of energy, multiple that by a population (even a small one), and even the massive investment into renewables that there is now will be quickly eclipsed.

Adding transactions that are so intensive to people’s everyday energy consumption would be a huge step backwards IMO.