Even if we put aside the tracking issues with CPI, someone would have to administer this. Armstrong says that an advantage over current stablecoins would be resistance to censorship, however there'd be no difference as the administrator could be leaned upon.

Also, in fiat terms, this product would have a "return". Buy for $1 in 2024, spend/sell in 2026 for $1.20. Where does that difference come from? Someone has to be on the other side of that to finance the difference, in essence shorting the CPI.

Swap products, futures, or street craps...someone has to be on the other side of the transaction.