Crypto increases or decreases in value just as any other good (or currency), based on demand, you can do Ponzi schemes with potatoes, you can’t say potates at their core are Ponzi scheme.
This is not true, because cryptocurrency is unique: it has no inherent value whatsoever. Potatoes have value as food, and so yes while they can be used as the underpinning of a Ponzi scheme, the presence of potatoes as a kind of currency does not immediately imply that you’re looking at a Ponzi scheme. You might be looking at a perfectly viable economy grounded, ultimately, in the value of a potato as a food.
There is no grounding for cryptocurrency. You can’t eat it, wear it, or live in it. You can’t use it to pay taxes, fees, or fines from a nation-state without first converting it into the fiat currency of that nation-state.
You might argue “well, you can exchange the crypto for those other things!” and the answer to that is: no you can’t, unless you have enough people participating in the Ponzi scheme. That’s how these schemes work. It’s a con game where the token only has a value if enough people believe it has a value. That’s a Ponzi scheme.
And cypto’s value is that it’s a currency outside the (at least the digital) reach of a countries institutions.
That is not a value. I have absolutely no need or desire for that, nor do the vast majority of people. People avoiding accountability from their community might view it as such.