Yes. Crypto was never productive.
But nice that your buddy financed a house with other people's dumb money.
In fact as the act of paying itself has become more restricted, it's often also a good way to make illegal payments for completely legal goods and services.
I was asked to audit a few proposals during that era and in every case I had to go back to the person asking me to say that it was a technical architecture L. Ron Hubbard would have admired. Just straight up making up words in most cases.
Far beyond "wait, is this actually a parody? how is this not a parody?" territory. 80% of them were effectively "tamagotchis + pyramid scheme".
This is why I say that you don't have to love LLMs, but you also can't compare them in terms of also bad. Jay-walking is bad and Jeffrey Dahmer was bad; they are not "both bad".
Was it universally obvious? Hindaight is 20/20 There were many block-chain startups funded, and even FAANG got caught up in the hype. FWIW, I was a crypto sceptic, but I had many arguments with believers online and in my social circles. Side note: a crypto enthusiast colleague bought a house off their crypto gains, it may be a grift, but a small number of crypto-believwrs got really wealthy, and you're not going to convince them.