I dont think the volatility is so much the issue as power and control. The USD/SWIFT system has given the USA both huge power via the ability to sanction countries that do not conform to its expectations and wishes and because SWIFT is USD based SWIFT results in all central banks needing to hold significant quantities of USD in order to participate- thereby USA can print (digitally) almost limitless USD to satify the volume of currency needed to maintain global trade payments which is a large part of the extraordinary privilege that the USA has enjoyed via its global fiat 'petrodollar' hegemony. This has enabled the USA to live way beyond its means, having trade and fiscal deficits for the last 50 plus years and able to because almost everyone needs USD in order to participate in global trade payments. China, imo, rightly sees this as unreasonable and now increasingly seeks to organise trade payments denominated in its currency. Why should China be forced to denominate trade with say Nigeria, (or almost any other country) in USD simpkly because the USA holds a quasi monopoly over trade payments? When I have traded with China in the past IO had to pay a US bank to convert my NZD to USD in order to pay the Chinese supplier. Why can I not simply pay the Chinese supplier in Yuan and convert my NZD directly to Yuan without a US bank acting as a compulsory middleman clipping the ticked every time? This is why China seeks to build its own trade payments protocol/s - so that it can cut out the US banks and remove the risk of sanctions by the US and reduce costs for its merchants and trade partners trading with them. Ultimately of course if trade is increasingly denominated in Yuan that delivers leverage, wealth and power to China and reduces US leverage, wealth and power. IMO the competition between the US and China is centred on who controls the global trade payments system and if the USA loses its current dominance over that it loses pretty much all other dominance as its position is so hugely dependent upon the dominance of the USD.