But hey, let's keep this up and see how long it lasts :)
here is just one example: https://news.ycombinator.com/item?id=32103472
And this doesn't even begin to discuss the broader DeFi ecosystem (https://www.youtube.com/watch?v=H-O3r2YMWJ4) and NFTs (https://news.ycombinator.com/item?id=35473327). Defi and NFTs haven't gained much traction outside of early adopters (and probably won't, because their reputation won't get redeemed) but the technology is nevertheless valid and operational.
But then do credit default swaps or collateralized debt obligations bring much benefit? Even gold and diamonds feels sort of marginal really. I'm not trying to excuse bitcoin, but to single it out as a pyramid scheme, no intrinsic worth etc. seems to ignore other financial instruments that might also have those qualities.
Collateralized debt obligations: created as a way to pool and securitize various types of debt, providing a means for financial institutions to manage risk and enhance liquidity. Just because a few banks and institutions used them to create complex tranches of debt which 'attempted' to reduce risk while massively misusing statistics and increasing it which resulted in 2008 doesn't mean that CDOs aren't useful.
Gold: I suppose you haven't heard about its applications in electronics and connectors, bonding wires, connectors, switches, thin film applications and coatings and hugely used in the production of medical devices and in the aerospace industry?
Diamonds: this one I agree semi-agree with. The only reason they have value is because the De Beers limited supply and there was demand -- but the demand is there because people use them as a status symbol and men use them to show their 'love' or commitment to their partners so this one is questionable.
I dunno, I feel like crypto is just an exaggerated version of most other asset classes, not at all uniquely terrible in its own right.