I didn't get a chance to read all of them but this was my reasoning on the ones I read: (note I'm excluding founder background from evaluation as almost none of the posts mention it; but it's generally considered a key factor for angels) WedWell: Large market, hacking it with initial customers, however no unique insight, no clear customer acquisition strategy in an expensive market, lots of dead startups in this spac…
If I could go back and rewrite that description, I would. The idea, at least on the economic side of things, is fairly fully fleshed out. The key thing, which I didn't even mention in my initial description, is the timer/expiration mechanism:
Rather than offer on-demand exchange between USD and GD, we will automatically exchange GD for USD after it remains in a user's account for a period of time. When an amount of GD is transferred from one account to another, that GD's lifetime resets. Consequently, the more that GD circulates, the less we will convert GD into USD and the less we tap into our USD reserves.
Here's a white paper (also linked in another comment) that describes it in more detail:
https://drive.google.com/open?id=0B2jhCMrrxoeONVNQTVd6NG5pNz...
Other online currencies are not both pegged to USD and handed out for free, so Greshm Dollar doesn't face some of the same adoption challenges that they do. Instead of thinking about Greshm Dollar as just another online currency, try thinking of it as a payment/credit system with a basic income attached to it. Or like PayPal but with free money continuously added to your account.
You can think about it that way for user adoption purposes, but, of course, that's not the whole picture.