Was it a year ago, or slightly less, we started spending a bit of time on cyrptocurrencies? Bitcoin is the most famous. Bitcoin has had a bad week, it lost about 30% of its value. It's down to about $US4000 since this time last year its lost about 80% of its value.

What surprised me a year or so back was how many people actually believed in it. No matter how many times we go through drama around dodgy looking ideas, investments or outright scams, we never seem to learn. Greed tops everything.

The trouble with bitcoin is it's only one of any number of cyrptocurrencies which those who jumped on board failed to, or didn’t want to, understand. Currency value is based on credibility and on regulation.

Cyrptocurrencies aren't regulated, they're beyond the net of governments and reserve banks. That, of course, was their attraction - you could allegedly beat the system. Until, of course, you couldn’t. Without regulation, it was cowboy, and cowboy lacks credibility and establishment credentials. Not that some didn’t take it seriously. You could buy the odd house with crypto. The reserve bank of England was looking at issuing its own.

There is a piece in the Herald that’s worth reading under the headline "Dirty secret revealed in new bitcoin crash", which suggests it's not just unregulated but criminally manipulated. If it's correct, that’s the sort of thing you get when there are no rules. Of course no rules appeals to some, but you are open to the lowest common denominator, and there is generally a reason we have rules around things like money.

And here's another irony: people who actually knew a bit about money like Warren Buffett of course rubbished them, and saw them for what they were. He was, of course, written off as a fuddy-duddy who didn’t get it. And yet, yet again, he is proven to be right. Psychologists could have a field day with this - why is it? Even when it seems bizarre, why is it when it seems farcical, made-up, rudimentary and snake-oil like, the pile on can't come fast enough. What is it about greed that overwhelms common sense?

 Why, when all the evidence is there to be seen, we still don’t want to see it? I suppose if you got your bitcoin at a buck, you're still quids in. But how many now are still standing by it as the currency of the future, and what will they say when it isn't?