This is the worry of globally-available USD stablecoins.
By swapping the volatility from crypto to lower USD volatility, they effectively create a funnel from riskier currencies into dollars.
Which is the same state that previously existed... except now facilitated by the crypto industry's global accessibility/UX and with less international regulation.
Blessing USD stablecoins at the US federal level was a smart move (from the US-perspective) as it creates a much bigger demand for dollars, and if the US didn't do it then China or OPEC would have eventually gotten around to it as an end-run around dollar hegemony.
Winners:
- Crypto industry (more volume to skim)
- US Treasury (more demand for debt)
Losers: - Countries with less-stable currencies (lose further control of monetary policy)
- China / OPEC (miss opportunity to push dedollarization further)
TBD: - Money laundering (once volume grows, KYC and traceability will follow)