A Ponzi-scheme is a specific type of scam, it's not a generic word for any kind of unsustainable investment or scam.
This whole thread looks like someone saying "No, a boat is not a car" and the other going "but it does have an engine, right? It's a car. Let's not argue semantics"
To be charitable, I think it’s more likely that this is an entire area where regulation hasn’t caught up so we don’t have any common names available.
These coins are ponzi-like in that only the earliest of adopters have any chance and only if they know enough to get currency out without hitting an inflection point that brings down the whole thing. But that’s where the similarity ends - the mechanism is different, they don’t operate like a Bernie Madoff and they’re honest about the whole process.
This is something else and while it’s Ponzi-like, it’s a different beast. I don’t think there’s anything particularly wrong with expanding the definition of Ponzi scheme for now, just so we have something to educate some irrationally exuberant retail investors…