I don't disagree with you, but there are many ways to skin a cat or in this case to make money. Ponzi schemes are one, but it isn't the only one. Greed or speculation in themselves don't automatically make Bitcoin a Ponzi scheme. Tether, on the other hand, definitely is a con and you can read about it over there: crypto-anonymous-2021.medium.c…

I still wouldn't touch Bitcoin with a ten-foot pole, but Proof-of-Work can explain part of the unrelenting growth the dollar value of Bitcoin has seen since its inception.