"While most stablecoins are pegged to a reference asset such as the U.S. dollar, flatcoins aim to be pegged to the “price of living” by tracking consumer price index and inflation data."
"“The closest thing to that is an inflation index bond, but if you created a coin that says OK this is buying power that I know I can save in and put my money in over a period of time and transact in anywhere, I think that would be a good coin,” he said."
My take: I-bond and other inflation index bond is issued by the treasury, so wouldn't there be some regulation issue. And fundamentally, bonds are loans to that company, so it's better they can prove they are profitable enough to pay the interest.
https://base.mirror.xyz/lt3JR-mZ51q9eIOtGO36L3ZVzCTXmZVnbIiXz6crqzQ
Even though flatcoin functions slightly different, the issuer still need to prove that they will not be insolvent for the future token swapping. But from the website there's nothing mention about how coinbase will ensure that, they are passing the responsibility to the issuer.