Centralized as in the Phillipino government gets to control the supply and make changes to it as it sees fit...
Decentralized as in the Phillipino government wants to do so without cost to itself, instead getting "the network" to support itself.
So basically, all the risks of a central-banked federal currency but costs borne by whoever is willing to mine it, Phillipino or otherwise? How will you make this attractive enough for people to mine considering the drawback of federal centralization?
The costs of rewarding those who secure the network must be significantly lower than the costs to print physical money in order for this to pass a cost-benefit analysis. There is increased security risk to the network due to bad actors who stand to gain control of the government or its financial authority if they successfully attack the cryptocurrency.
Since it's government money, it will make changes to it as it sees fit. The government might consider helping to secure the backbone currency: Viacoin. I'm surprised you're asking the above questions since you seem well-versed in crypto technologies.
We don't see a government-backed currency as risky since 100 million Filipinos are using one. It seems Bitcoin is more risky since it looks like only traders use it. The Viacoin ecosystem has its own purpose and rewards. Miners should look to it rather than E-Peso. If Viacoin fails, E-Peso fails along with other assets/coins riding on its blockchain. But we're investing in the future.
Viacoin will be huge