Physical centralization actually proves to strengthen the value proposition of this due to its oil backed price tether. Its actually much like SBD except rather than being backed by a fluctuating amount of STEEM as it relates to $1 USD. In the case of this currency its supposed to be redeemable for Venezuelan oil.
Keep in mind that SBD is not worth $1 USD its worth the equivilent in STEEM, so just like how for us to trust in PETRO we have to trust in the leadership of Venezuela to honor the market, in the example of SBD we have to trust the leadership of the STEEM blockchain to honor the market.
Now while it is true that leadership of the STEEM blockchain is a more decentralized form of centralization, they are dealing with an intangible asset so decentalization is makes sense, but when dealing with a tanglible assets such as oil, in order for the backing to mean anything there must be a physical centralization