It's been a while since I've done serious economic analysis. Please correct me if I'm wrong.
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Also, the whole thing is predicated on a web of trust to prevent Sybil attacks. Fine, but PGP has shown pretty conclusively that a web of trust like this is a failed model. A single trust authority makes far more sense for this application.
In the PGP case, casual users like myself don't personally know anybody who uses PGP. I would have to go out of my way to acquire a reasonable degree of trust on my key: I'd basically have to start asking people I hardly know "hey can you sign my key?" which I'd rather not do. That's fine, because PGP is for hacker nerds and not everybody needs or wants to be a hacker nerd.
The problem, however, is that if this is to be truly universal then you need to guarantee universal access. What if I've been in prison for 5 years, I can't get in contact with any of my family, and my old private key is long lost. So I start up a new account and... what? Who trusts me? I basically have to start asking random people to trust me. So people have to trust each other. Then what's stopping a con artist from going from town to town, getting store owners and locals with bleeding hearts to trust each of his multiple duplicate currencies. The Sybil attack can proceed with trivial social engineering.
You're in a Catch-22: either people are skeptical, and the system is decidedly non-inclusive, or people are trusting, and the system is insecure. You need centralized trust: it's the same problem we have today with domain names. You need an authoritative list of valid domains, and a single source of truth for accessing that list.
The nice thing about a trust authority is that it doesn't need to be physically centralized. Just record everyone's citizenship on a blockchain like Ethereum. But at this point I'm just speculating.