Shortly after the latest bout of the eurozone debt crisis — Greece’s battle with the rupture of the single currency in summer 2015 — a colleague bet that within a decade the euro would lose at least one member. So far, it’s been quite the opposite: the monetary union just got a member, with Croatia joining at the start of the new year.

This force of attraction is not a one-off. Remember that during the most difficult years of monetary union, one Baltic country after another stepped forward and joined. The next Bulgaria will no doubt be allowed to adopt the euro soon. (A number of smaller and poorer European jurisdictions also use the euro either through unilateral adoption or as a result of the informal private sector euro process.)

One could say that there is nothing to see here – that it would be surprising if small, open economies did not want to participate in monetary policy making for the currency that dominated their trading relationship. But the notion is such that the euro in its current form is so doomed – especially among Anglo-American economists – that some reflection on its recent expansion is timely. Because old misgivings are becoming increasingly unconvincing, while ongoing changes in how money works speak to the advantage of the euro.

In recent years it has become – or should have been – increasingly clear that monetary ‘independence’ in the sense of having one’s own floating currency is not all it has to be. The advantage is supposed to be that a depreciating currency can offset negative shocks by boosting exports. As the fall of the pound sterling in 2016 after Britain’s EU referendum showed, however, in a world of long and complex supply chains across borders, currency depreciation could make your population poorer by raising the price of imports, with no support for export volumes. .

Meanwhile, the benefits of monetary integration are being demonstrated by the energy price crisis in Europe. Take Slovakia. Yes, it has to deal with similarly high inflation as its non-euro neighbours. But it does so while enjoying a much lower interest rate (2.5 percent for the European Central Bank) than the Czech Republic and Poland, where borrowing costs are three times higher, or 13 percent in Hungary.

Size matters in a global economy whose rhythm is still set by the US financial cycle, and only the monetary union of euro economies gives the European Central Bank a degree of independence from the US Federal Reserve.

Second, it is now easy to see the vulnerabilities that emerged during the eurozone crisis as a type of crisis that could hit anyone, including economies with independent floating currencies, rather than a unique weakness in the euro.

Italy remains the country where pessimists believe the combination of high debt and low growth should eventually cause the euro’s demise. However, last summer it was not Italy, but the new populist government in the United Kingdom that severely shook the markets with its irresponsible policymaking. In the end, the Bank of England had to step in to contain the sovereign yields.

While the ECB may still be tested in this regard, it has the advantage of being more independent of its political masters than any national central bank. If anything, the Bank of England has more reason to fear monetary finance charges – which it was evidently keen to disprove – and which complicated its message when it turned from selling gold bonds to buying them in the market’s fright in the fall. By contrast, the European Central Bank created a permanent tool to deal with similar events last summer, with little controversy.

All this suggests that the euro will become more, not less attractive over time. The appeal of different currencies will be further altered by how they manage the next big leap in central banking: the introduction of an official digital currency. So far, only peripheral economies like the Bahamas and Nigeria have gone all the way — although China is clearly primed for its capacity to expand the digital renminbi it has been experimenting with.

Among the rich economies, the European Central Bank has quickly moved to the top spot. Finance ministers swung defensively behind the digital euro after Facebook’s move in 2019 to create a private global digital payment system. But their support has now been bolstered by looming business opportunities in an economy of “programmable” safe money.

Formally, the digital euro is still only in the exploration phase. But politically, it has reached a point of no return. After Croatia, future entrants to the monetary union will enjoy having a developing digital currency in the bargain.

martin.sandbu@ft.com