Here's how arguments work. You read a claim and disprove it by offering a counterexample. The weaker the counterexample, the weaker the disproven claim.
In the case of Bitcoin a weak counter example is to show that even a grossly inefficient method of money transfer has superior efficiency. A stronger counterexample based on Visa's less than 2Wh per transaction numbers absolutely destroys the claim that Bitcoin's efficiency is reasonable.
It's laughable that anyone would even defend Bitcoin instead of recognizing the inefficiency. It's laughable in the exact same way the Tesla suggestion is laughable, except Bitcoin is even worse.
Not a lot, but it's definitely a thing. Speaking about majority, these days, most people and companies are accumulating Bitcoin only because in 5-10 years it'll worth much, much more. And that makes a lot of sense if you think about it. The shift to a digital form of currency will eventually happen anyway. I do not believe Bitcoin will ever become a global currency, but I strongly believe that it's going to stay with us for quite a long while. The blockchain technology is in its infancy and is experiencing a lot of research on all fronts.
I do international transfers quite often. Every time I try to send a more or less large amount, it becomes a pain in the ass both for sender and recipient. You have to prove that you are not a unicorn.
People use Bitcoin because it's freedom from the existing banking system, plain and simple. When you are sending money via a bank, it's like someone is watching you at a bathroom. It simply doesn't happen with Bitcoin.
Bitcoin will be the force that will make all the miners completely switch to a green energy (and that's already happening).