Encrypted currency Bitcoin has experienced tremendous growth, hitting almost US$20,000 (HK$155,000) per coin last week.

Although investors were disappointed after it stopped short of shooting past that mark, it has proved again that it is pricier than gold despite the latter also having experienced a strong ride in recent months.

The strong performance of Bitcoin is partly down to broader recognition of the digital currency from established transaction platforms.

For example, PayPal last month moved to increase the limit of how much Bitcoin customers can buy.

In nearly all articles about Bitcoin, there is always a word, or its synonyms, to be found: untrackable.

Perhaps it's because it leaves no footprints in the system and, therefore, its use cannot be traced that there has been a constant demand for Bitcoin in some sectors that are not confined to the illicit dark world.

Interestingly, a digital currency exactly opposite in visibility is gaining traction in the world's second largest economy, China.

Two words regularly appear in articles about the digital yuan which, in the mainland, is officially known as the Digital Currency Electronic Payment, or Dcep - traceable and controllable.

If Bitcoin is designed to flow under the radar, the digital yuan is fully visible, with regulators knowing its every movement. A pilot scheme of the currency in some mainland cities, including Shenzhen, has been declared a success. It involved hundreds of participants who were randomly selected to be issued an electronic red envelope containing 200 digital yuan. The participants shopped as they usually did with Alipay or WeChat Pay.

According to Bloomberg, Macau could be the first Chinese city outside the mainland to test its use.

Although the Macau government has dismissed the report as untrue, could there be a grain of truth in it?

Indeed, it would make good sense to test the digital yuan in Macau. Its gaming industry provides a perfect platform to test it on a broader basis - more than ordering food on Meituan or buying groceries at retail shops in Shenzhen during the previous trial.

A reason that Beijing policymakers may wish to include Macau in the trial is that the flow of digital yuan can be controlled. And when it comes to the casino tables, unless Beijing finds a way to control the flows, tonnes of cash could drain away.

As said, since the movement of digital yuan is 100 percent visible to watchdogs, it is possible to maintain control over it by, for example, limiting how much a mainlander is allowed bet at the tables.

This could be a double-edged sword for Macau. On one hand, Beijing may - with greater confidence - allow mainlanders to visit Macau on a larger scale. On the other hand, casino revenues will suffer if bets are capped.

In light of Macau's technical denial of the report, it is more likely than not that it will be awhile before the digital yuan begins circulating in the enclave - but this is only a matter of time.

Safe bet digital yuan will hit Macau