I actually just wrote a post on this: https://steemit.com/cryptocurrency/@prof-pieters/venezuela-announced-that-it-plans-hopes-to-launch-a-new-cryptocurrency-named-the-petro
In short, I'm not sure that this will work. More importantly, it's not clear to me that Maduro is actually calling for a cryptocurrency, it may just be a state-run and controlled digital currency.
Actually, I read your post and you raise very good questions about this. I guess we´ll have to wait till this project moves forward and more information is released about its specifics.
I could speculate about several of those issues:
We are on the exact same wave-length.
With all those of assumptions, the launch and adoption Petro is a feasible outcome. Except. The Venezuelan government wants to back the Petro with natural resources and oil. What the heck does that look like under the system assumed above? How is is the government going to destroy a Petro that is traded in (or converted) into the backing good? Or will it simply hoard the Petro's and somehow have the discipline to not re-issue it into the economy? That's the part I keep getting stuck on.