It relies on people to keep buying the second coin (Luna) in order that its price is supported to a level that the peg mechanics work. But there's no fundamental value anywhere in the system, you can't pay your taxes with this, it's not backed up by a government with a monopoly on violence nor by a large economy of productive output. So the "trust us, it's valuable" part (which ends up being the only part that matters) doesn't work.
It seems Ponzi scheme has become a misnomer for "scam".
Whereas "scam" has become to mean "thing I don't like".
Whereas “thing I don’t like” is used to dismiss people calling out scams.
There's also Anchor, which is the third piece of this Ponzi. Anchor promises 20% yield on UST, and this is what generates demand for UST. However, the yield contains risk which is hidden on purpose or not generally understood. Ponzi schemers profit from this information asymmetry, and work to maintain it.
Most of the yield in crypto is generated from dilution, and therefore the real return can be positive as long as there are new investors, which offset the effect of dilution. Now, classifying them as Ponzi schemes depends on how these assets are marketed and sold. Expected return of these kind of schemes is zero, which is how they should be marketed.
I'm not defending the coin, but in what way is this a Ponzi scheme? It may be hair-brained and an absolutely terrible investment, but from OPs description it does sound "novel" to my novice ears. How is this specific concept (pegging one coin to $1 by using a second coin) a ponzi scheme?