Venezuela Petro Cryptocurrency As I understand it, a primary feature / requirement of cryptocurrency is that it is not controlled by a government actor: it is decentralized.  If this is true and the Petro is controlled by a government (i.e. it can 'mint' more coins):  

What is the reason to implement cryptocurrency in a manner that allows for greater ease of 'printing money'?
Cryptocurrency is never a good medium of trade exchange compare to printed notes.  

Anyone follows the history and trend of cryptocurrency can tell you that, cryptocurrency has become speculative medium than a currency itself. The best scenario to describe the speculation is various Initial coin offering(ICO) that went boom and bust.

A cryptocurrency such as Petro coins does not fair better than others, even Venezuela government say it is "backing" with something like oil. Because the logistics are too complicated and costly. Thus, Petro coin is anything but just yet another ICO to attract speculators to pay it in dollars(or any foreign currency that Venezuela needs). 

In short, something like Petro is not going to replace the currency, but as a tool or "virtual commodity honeypot" used by Venezuela to get foreign currency without any sound production.