Crypto-currency fan: Entrepreneur Crystal Fong decided to try withdrawing bitcoin after both her ATM cards were cancelled while on a trip to Tokyo. "But I was on my last 1000 yen in a ridiculously expensive city, with two cancelled debit cards," she says. Opening a bitcoin wallet and road-testing the digital currency seemed far less risky than trying to survive "on 10 bucks for five to seven working days", she adds. So, using the on-the-go bitcoin wallet CoinJar, she withdrew it in yen from a bar-room bitcoin ATM in buzzy Roppongi – behind her, chatter arose about the potential and downsides of the crypto-currency that spawns controversy and curiosity. While using bitcoin was less convenient than handling a normal ATM, adopting it felt "mighty liberating", she says, adding that it gave her instant access to ample cash without bureaucratic obstruction, at low cost. For 80,000 yen she was charged about $30: five dollars cheaper than she would expect to pay with a big bank.

Cut out the middleman: Asher Tan, CEO and co-founder of CoinJar says Australia now has four major bitcoin exchanges. "True, the difference in fees for this amount is marginal, but think about what this could mean if the amounts were grander, and transactions more frequent," she says. Critics contest that bitcoin is just too volatile — according to the Consumer Financial Protection Bureau (CFPB), the one-day price drop in 2014 has been as big as 80 per cent. Fong's comment on the topic is that, if you are an ardent traveller wanting to move cash cross-border cheaply and quickly, you just have to ensure you send and receive fast – no problem because a transaction can be done in a flash, according to Fong, who touts bitcoin as universal. The chief executive of the Digital Currency Council, David Berger, agrees: over 100,000 merchants accept bitcoin payments, according to Berger, who describes bitcoin as global and says it can buy everything from a pizza to a condominium, online or at a traditional shop. "It's as easy as sending an email from your smartphone," he says, adding that bitcoin enables more than marginal savings because it involves no bank or money transmitter sat in the middle of the transaction charging high rent for network use — the value is transferred directly from the sender to the recipient, Berger says, which means that bitcoin can significantly undercut the market, it seems.

The chief executive of the Australian bitcoin company, CoinJar, Asher Tan, nuts out what a cross-border payment through an established global transaction service may cost. For example, Western Union charges a $10 fee to send $100, he says. Then there are conversion fees and withdrawal fees at the other end. Based on CoinJar's rates, sending the same sum with bitcoin would cost $3.10, according to Tan, who like Fong takes the long view. "Over time," he says, "that saving adds up — it still requires some groundwork by both parties, but if you're organised, the savings can be material." If the recipient lacks bitcoin experience, you can actually set up a bitcoin account in their country and arrange the withdrawal on their behalf, avoiding the usual fees and saving them handling bitcoin, he says. Bitcoins can be cashed in over 225 countries, from Andorra to Zimbabwe, he adds. Everyone knows that bitcoin is volatile, he admits, but echoing Fong describes the drawback as irrelevant if both ends deposit and withdraw fast. As with ordinary currency, always check which exchange has the best rates — BTCTransit is a good resource for information on available exchanges and their rates, according to Tan.

Like Fong, he says bitcoin might not be for everyone. First, do your homework — test the exchange you have in mind with a negligible sum of money. Then, start small to see if you gain enough savings, he says. Security strategist Ty Miller says that, so long as you keep your currency in bitcoins, you will incur minimal fees. Still, Miller says, the volatility issue that can occur when you turn bitcoins into hard cash is a serious catch. At any time, the price of bitcoins may dramatically rise, he says, adding that you run the risk of a bitcoin crash. He also warns that bitcoin exchange withdrawal fees vary greatly — from $1 to $50. Then, there is the question of security. Bitcoin is reasonably safe, he says, but Japan's Mt. Gox exchange had hundreds of millions of dollars worth of bitcoins stolen, he notes, adding that bitcoin remains in its infancy, leaving it prone to abuse by malicious users. The global directory of bitcoin exchanges [howtobuybitcoins.info] cautions that, when sending money to an exchange, you are trusting the operator not to steal your funds, and that their site is secure. The directory advises you glean the operator's real-world identity — and ensure recourse is available. Bitcoin nitty gritty

Designed to be user-friendly, Bitcoin works like this: the sender sets up a bitcoin account called a "wallet" and makes a cash deposit which is converted to bitcoin. The sender then dispatches the bitcoin to the recipient's bitcoin account, and the recipient withdraws it at a local exchange. The currency created in 2009 owes its existence to a mystery individual or consortium using the Japanese alias Satoshi Nakamoto. Propelled by its touted flexibility and convenience, Bitcoin went viral. According to CoinJar chief executive Asher Tan, Australia now has four major bitcoin exchanges: CoinJar, Bit Trade Australia, "igot" and CoinTree. In August, the Australian Taxation Office ruled that bitcoin is a commodity, not a currency: people who transact with Bitcoins will have to pay goods-and-services tax on the Australian dollar value of a payment. The news fed fears the industry will be driven offshore or underground in an echo of its iffy past. Bitcoin played a key part in the running of the now-defunct online Silk Road black market website.