Gambling is heavily regulated in most countries.
MLMs are barely legal, and subject to rule of law.
Mileage programs are actual debts and mentioned in financial reports, as we saw during COVID.
Cryptocurrencies on the other hand, are unregulated mini-Ponzi schemes - while stablecoin and exchanges have often been found to be insolvent.
Mileage: https://youtu.be/ggUduBmvQ_4
There are, absolutely, crypto Ponzi schemes. (And stablecoins are largely such things) However there are also valid uses of crypto/Defi. I've used them myself to send funds easily. They are enabling truly symmetrically fair exchanges etc.
If you don't like crypto, don't buy it, don't mine it. Following eth 2.0 the energy usage will be minimal and it won't be harming you. Preserving positive freedoms generally and avoiding negative freedoms (constraints on others) is a good thing imo.