According to the Venezuelan Petro whitepaper, the Petro (PTR) will be freely tradable. It will allow Venezuela to bypass financial censorship on their US dollar transactions in New York. Venezuela will finally be able to pay for their food imports again.
All of this assumes that the State oil company, Petróleos de Venezuela, S.A. (PDVSA), will work overtime to swiftly accept PTR payments in exchange for their oil deliveries.
The presale has commenced already (20 Feb 2018) and the public ICO will be floated next month (20 Mar 2018).
The Venezuelan State accepts the restriction that it will not be able to make new emissions of PTR. Of course, this should be verifiable in the NEM ICO smart contract.
The NEM blockchain uses a Proof-of-Importance (PoI) system to prevent double spending. I would like to see the math thoroughly peer-reviewed in order to verify that the probability over time that attacker of the honest blockchain successfully subverts it, is a Cauchy sequence that converges to zero. There haven't been any really bad complaints about NEM yet, but in the cryptocurrency field, it usually means that few people have had a serious look at it.
Concerning the NEM software, the current implementation of the server is closed source. The developers have promised that the C++ rewrite, "Catapult", will be open source. This redevelopment problem has now become an urgent matter. It is absolutely unacceptable for smart contracts of sovereign coins to run on secret source. Doing so, violates freedom of information. Therefore, the open-source rewrite must urgently be completed and be published for peer review.
The secure client-side NEM wallet seems to have a proper offline signing procedure but the link to the source code seems to have disappeared from Github. The main NEM wallet, nanoWallet, exposes the seed/secret to the network and must be considered fundamentally insecure. This wallet should not be used for anything more than very small, nominal amounts.
In my impression, if Petróleos de Venezuela, S.A. (PDVSA) accepts PTR payments for their oil, the coin will be perfectly viable, and be suitable for bypassing New York censorship on US dollar payments.