I fell out with a friend in Hong Kong some eight or so years ago over “investing” in Bitcoin . I said it was a dumb thing to do. She maintained it was the future of all currency transactions and that I was the idiot. It spiralled down. I have no idea how it turned out for her, as she unfriended me on LinkedIn, blocked my mobile phone number and we haven’t spoken since. I admit, though, that I reacted on instinct. It took me a long time to get my head around cryptocurrencies , blockchains, coins, tokens and other...