it's a cool idea but i don't think it can be done in a 100% decentralized way. i'd prefer to trade back and forth between DAI and ETH etc to hedge against fiat inflation.
Not really sure how using a decentralized network of oracles is in any way the definition of centralized.
Sure, if you're taking information from a single oracle, that would be centralized, prone to censorship and manipulation etc.
you can call the oracles a "decentralized network" but that's a red herring. "centralization" refers to the dynamic between nodes and oracles, not the dynamic among oracles. nodes are vulnerable to collusion among oracles the same way nodes are vulnerable in a federated consensus. they need to trust the authorities to be honest.
what kind of reliable sources? are we gonna use third party APIs to feed directly into these smart contracts? that sounds impossible to attack.