I agree with the argument that it doesn’t make sense for the United States. Other countries using USD already don’t have control over monetary policy.
Oh yeah, totally fair and an interesting difference between Diem and other cryptocurrencies. I still think volatility and transaction latency/costs are an issue, but assuming we fix those (and stipulating they can be fixed) it doesn't seem unwise for smaller countries to use cryptocurrencies. It would more or less be gold standard monetary policy in a box, and while that system has drawbacks, a nice thing about it is it's pretty hard to corrupt. It would be harder (not impossible, but meaningfully harder) to manipulate currency and politically choose winners and losers via monetary policy, which is a big deal especially for growing or newly stable countries.
But for those countries, it really seems like choosing Diem is the worst of both worlds. You're still pinned to the Dollar, you're still at the whim of unaccountable controlling stakeholders, and you have all the downsides of cryptocurrency on top of it. I struggle to think of a group outside of Facebook that Diem is at all good for, honestly.
What distinguishes one fiat from another is "do important people believe in it". There may come a day when that's true for cryptocurrencies, but that day is not today.
Further, I doubt it ever will come, because cryptocurrency's core scarcity hamstrings monetary policy. No competent government would ever accept such restrictions. This is a feature for cryptocurrency enthusiasts (digital gold bugs) but a huge shortcoming for everyone else.