The lightning network is what carries the load of day-to-day transactions for the bitcoin monetary system.
On-chain transactions (which are what you are referring to Bullion) are for final settlement, given the 10-60 minute settlement time and higher fees involved.
It should also be noted that the energy use of the bitcoin network does not scale with that transaction volume, so although it's a neat mathematical equation to divide the energy use by on-chain transactions, it is not how the system scales.
The lightning network, which is where day-to-day transactions take place, is vastly more energy efficient, and faster, than VISA, Mastercard, Paypal etc, and has far more capacity for scaling.
Although bitcoin works in a vastly different way than the current financial system, if you want to make comparisons, you must compare the right layers with each other.
Lightning is the comparison with Visa/Mastercard/Paypal and any other transactional fiat network.
On-chain is the comparison with SWIFT and the full military industrial and power structures that support the petro-dollar. That means you should be comparing the energy use etc of bitcoin mining with all military, government, central banking, and any other power structures in the fiat world, to get a true picture of the possibilities with bitcoin.
On-chain transactions (which are what you are referring to Bullion) are for final settlement, given the 10-60 minute settlement time and higher fees involved.
It should also be noted that the energy use of the bitcoin network does not scale with that transaction volume, so although it's a neat mathematical equation to divide the energy use by on-chain transactions, it is not how the system scales.
The lightning network, which is where day-to-day transactions take place, is vastly more energy efficient, and faster, than VISA, Mastercard, Paypal etc, and has far more capacity for scaling.
Although bitcoin works in a vastly different way than the current financial system, if you want to make comparisons, you must compare the right layers with each other.
Lightning is the comparison with Visa/Mastercard/Paypal and any other transactional fiat network.
On-chain is the comparison with SWIFT and the full military industrial and power structures that support the petro-dollar. That means you should be comparing the energy use etc of bitcoin mining with all military, government, central banking, and any other power structures in the fiat world, to get a true picture of the possibilities with bitcoin.
Also, what happens if there is a incomplete transaction in bitcoin are there provisions like chargebacks with credit cards?
They will exist, but they will not need to consume nearly as much energy, require nearly as much funding, or create anywhere near the volume of emissions, as they do under a fiat standard.
Under a bitcoin standard the military's role in the world would be massively reduced. The world's currency now is the petrodollar, hence why we have such conflict in the middle east, and enormous military spending concentrated in that area, or related to that area. With bitcoin, military power to take or protect financial assets is of no use. It is a peaceful currency - it cannot be taken or held by force. The war for bitcoin will be a peaceful race for energy production, and because bitcoin is incentivising for green/wasted/renewable/stranded energy, this will also be the best thing for our environment that you can imagine. Subsidies and legislation will pale into comparison to what bitcoin will do for the greening of energy production. It is the key to the future in my opinion and I cannot wait until we start to see this playing out.
Currently the US and other countries deficit-spend to boost their military. It is astonishing how much is spent on their forces. Under a bitcoin standard they would simply not be able to afford it, and they would not need it.
Regarding your second question, a bitcoin transaction itself cannot be "reversed", in the same way that the exchanging of cash between two people cannot be "reversed".
If you agree that the exchange should not have happened, you give it back. If there needs to be legalities and governance around that process, then it will be built or enabled. And the record would be there in the blockchain - a transaction where it was paid, and a transaction where it was paid back.
In terms of transaction reversal, perhaps think of bitcoin as cash - physical money. When you give it to someone, it's the same as giving them physical cash. If you want it back, then you need to ask for it back. You can't just take it, otherwise you shouldn't have given it to them in the first place. If there is a legal case that they should be giving it back, then it is the same as now - you can take it up with authorities.
These are all excellent questions and queries, same things that ran through my mind once. It's quite a mental hump to get over when you start to really understand bitcoin and the possibilities.