1) The Yemen number is for the whole system. The energy to send one transaction is tiny and much smaller than using the existing remittances system.
2) With a bank, it's not even clear you could send $5 to Yemen as there's a civil war going on. And if you did find a money transfer company willing to do it, it would be very expensive. With Bitcoin, as long as the person in Yemen has a phone and can get online, you can send them any amount, it will cost ~$2, and take minutes to do.
My favourite benefit of Bitcoin is bypassing the hideously inefficient and corrupt Wall Street financial vampiric system that provided the world with the Global Financial Crisis for which it suffered the punishment of being given billions of dollars by the US Government.
Attacking another user like this (edit: and https://news.ycombinator.com/item?id=28567074 - yikes!) will get you banned here, regardless of how wrong they are or you feel they are. Whether or not you owe that person better, you definitely owe this community better if you're posting to it—much better. So no more of this, please—we're trying to have an internet forum that doesn't burn itself to a crisp.
Please get some perspective. Read more actual facts and data from various different angles, you've obviously dived deep into one side with little consideration for any other.
You give me the kind opportunity to quote a favourite lyric of mine:
The do-er and the thinker: no allowance for the other
The append-only ledger is surprisingly efficient, to the point where you can process the entire thing on a decent laptop in a couple days.
And judging the costs bank are able to charge for international wires, even when comparing them to the horrendous fees for Bitcoin (Core, BTC) on-chain transactions, I'm not convinced Bitcoin is that much less efficient.
