If so, it looks like the USD is a third-party-adjustable view of the underlying Bitcoin if I and a second party ever enter a contract that is denominated in USD.
It would be better for us to avoid the possibility of third parties messing with the intent of our contract by just denominating in BTC.
So… I do not get the point? It smells more like a scam to use USD in such a regime, as my counterparty in any contract might be in cahoots with the third-party, the government that defines the exchange rate of USD to BTC, to change the effective value of amounts in my contract with them.
Again, this seems to me to stink of rule of man over rule of law. Unless the USD to BTC is fixed (and USD would be just a different unit of BTC, like millibitcoins, satoshis, millisatoshis), this allows external actors to mess with the exchange rate, and for lobbyists to those actors to incentivize, via open legalized bribery, the movement of the exchange rate towards some direction that makes no sense.
Alternately, there could be some metric or key input that can be used to adjust this, but this moves the issue to an oracle problem: you now have to trust some entity to give you accurate information of some metric. It may be possible that measurement of this metric (or inputs to this metric) are corruptible and lobbyists will focus on those to the detriment of less-powerful beings who cannot afford lobbyists.
“Keep it simple, stupid” seems like the best reaction to this. Just denominate in BTC?