Same that happens when you lose anything else of value- it's lost unless you can get it back. I don't need a central authority to decide that I might be able to get my money back without my password, because then someone else can do the same (via social engineering or otherwise, like internal saboteur)
>What if a 51% attack happens, in which 51% of the processing power in a blockchain network come under attack by a group with immense computing power?
An incredibly unlikely event, given the vast size of the network. Though it is a valid concern.
>This is to say nothing of the environmental aspect of Bitcoin mining, which uses more energy than entire nations.
Agree on this point, FWIW, though PoS aims to fix it (which sadly is moving pretty slowly)
>Or the fact that groups like the Al-Qassam Brigades are using cryptocurrency to finance their operations and solicit donations.
What about the fact that banks assist billions in tax fraud (and pocketed millions in bailouts)? The crypto can be blocked at exchanges in the future making people more wary about the issue.
I hope I don't come across as a crypto shill as I own no crypto, but the author argues against crypto as a whole (instead of, say, crypto evangelists).