Cryptocurrencies like Bitcoin, Ethereum, Ripple and Litecoin haven't even been around for a decade, but they are valued somewhere about $135 billion already, which isn't small change.
For an outsider used to government-issued money that's regulated and controlled, cryptocurrencies must seem like total mayhem.
There are no physical notes or coins, only digital acknowledgments of "proof of work" which means that someone has "mined" or solved a cryptographic problem using lots of computer time and electricity, and been rewarded with a unit of cryptocurrency.
What's the attraction then? No central banks or worldwide monetary authorities control cryptocurrencies or the transactions done with them. With cryptocurrencies that have a fixed supply like Bitcoin, it's a matter of getting in early while the value is relatively low and there are coins left to mine.
Oh, and digital criminals, like ransomware extortionists, like cryptocurrencies too, as they're easier to handle and harder to trace than "real" money. For most non-keyboard criminals though, cash is still king.
That's the libertarian-style theory behind cryptocurrencies: wrestle away the control of money and dealings from banks and governments, fix inefficiencies within the current financial system and the always-perfect invisible hand will set things right.
In reality though, cryptocurrency values seesaw up and down, often with little notice and for unclear reasons.
If you don't keep an eye on appreciations and depreciations as a cryptocurrency holder, you could get badly burnt.
Speculators love this but for normal people, having a currency that jumped from US$653 to US$2,795 per unit in a year like Bitcoin did would be madness.
Nevertheless, a number of believers mine coins and keep cryptocurrencies in digital wallets, in the hope of cashing out big.
That works until a software bug is exploited by criminals to empty people's cryptocurrency wallets to the tune of millions of dollars. This happened recently with a hosted Ethereum multisignature wallet, causing losses of $42 million in the blink of an eye.
Amazing to think that people keep assets worth millions in bug-prone wallets on other people's computers without insurance, but that's cryptocurrencies for you.
Despite several very public cryptocurrency hacks and heists, the love for the tech shows no sign of abating.
The decentralised database of transactions that underpins cryptocurrencies, blockchain, is hot stuff currently. Banks, governments and geeks love blockchain because the technology seems to solve lots of issues around shifting not just financial but other ownership transactions and records as well to the internet.
Blockchain remains a new technology with inherent flaws to be careful of, as Australia's Commonwealth Science and Industrial Research Organisation's Data61 arm warned recently in a report to the government.
For example, for blockchain to truly take advantage of transparency and decentralisation, it would need to be public with anyone being allowed to take part. That means both the good people and potentially the baddies, and it's not what banks or governments would like; they'd want to operate private blockchains instead which seems to defeat the key purpose of the technology.
We should explore cryptocurrencies and their adjunct tech like blockchain, and pick the best parts of them but not be seduced by the technology. They will need to stand the test of time and trial of abuse that the internet brings before anyone should trust them.