Two of the main features of all these coins are anonymity and untraceability. By using this proposed feature we would instantly give up both for somewhat improved security. I would chose other solutions for securing my wallet.
just to politely correct the many errors i see here in this above statement - I'd really doubt that these are two of the main features of Cryptocurrency for a user.
id say a much closer two if i had to guess would be:
1. Not centrally issued by a a Central Authority controlling distribution quantity and supply.
2. Not able {very difficult} to be immediately controlled by any one entity.i'd rate "anonymity and untraceability" a fair way down the list, of what normal citizens want.
and then there is also the point that a simple SMS Verification system - does actually not disclose anything about anyone I'm not sure where you live but where i live out 711's hand out Sim cards like they are going out of fashion . sure "Smart" devices are traceable , but what about "Dumb" devices - broad SIM triangulation at best .
and then there is the fact that the OP said it would be
"Optional" - anything Optional gets the "CryptoSteve" tick of approval. : D and of course then there is the fact that most people understand that our poor confused government agencies are trying to know every last thing we do, at a point that equation will balance and citizen will opt out of the system , thus the system will in plain sight not function. , when i say opt out i mean , the environment they are in will seem more and more worthless , and as they see less and less benefit , they will simply stop participating.
