These venues can be distinguished from a Ponzi scheme because the participants are traders in a market, not investors in a company or managed financial product.

But retail traders can use the markets to make bets on overall economic growth. Buying a stake in hundreds or thousands of public companies is a clear bet, and you actually do own something in a legal sense.

With crypto trading, it's unclear what your bet is -- other than the continuation of the Ponzi scheme. You don't own anything, and the coin has no value as soon as people stop believing in it.

If retail investors understood that nature of crypto, I'd be fine with them gambling on it. But most of them are tricked into believing there is underlying value in the coin when there actually isn't (see also: NFTs).

The state (us government) has made it clear that there is no distinction it can stand behind anymore

sometimes earlier investors get paid out by newer investors

whether it’s a high yield investment program, a poorly run hedge fund, or the entire corporate bond market, or social security, or herbalife, or defi

The debate over the name of the payout system is no longer productive, as ponzi scheme - as a pejorative term - doesn’t tell you anything

"Fraud" works for me.

All nascent markets are wildcat melees. https://en.wikipedia.org/wiki/Wildcatter

Useful markets are eventually regulated. To save the market from itself, to calm down the townsfolk brandishing pitchforks and torches, to assert central control over a proven grift.

Time will tell if all these crypto kittens prove useful for more than fraud.

Your proposal of using it would at best case simply dilute that word until it was no longer useful, and worst case open its users up to libel due to being a legal term