Any non-tangible good and even many tangible goods are fiat wealth. That includes precious metals, gems, stocks, bonds, contracts (e.g. promises), oil, etc. including HOUSING. Gold is really only worth what someone else thinks it's worth, on the global "agreement" market (often manipulated). Futures are just contracts - remember when oil went NEGATIVE in 2020? Stocks - you're joking. Those hold no real value, the value is all tied up in "part ownership (a laugh, you don't own **** in a company unless you have a major shareholder position)" and companies often fail and dissolve. Regardless, probably 95%+ of shareholders use stocks as "investment tools" to increase wealth, most don't care about the "ownership" aspect (which is generally trivial), and stock prices are ONLY worth what someone else is willing to pay, and they can often fluctuate 10% or more intraday on greed, fear, and speculation (and not necessarily on anything tangible within the company). It was just a decade or so ago house prices collapsed 50% on average and now they're up 200% from those periods. What changed to cause this? It's mostly fear, greed, and speculation.
I poo-pooed the cryto (Bitcoin) for 10 years and sat on the sidelines with the same naive notion, meanwhile watching people make MILLIONS or BILLIONS of dollars. It may not have "real world" value on screen, but when someone converted those electronic numbers into cash, and then bought mansions and cars and took trips it sure as heck had value. And it truly still does. Warren would be speaking hyperbole or be a fool if he wouldn't take all the Bitcoin for $25 (which is the price of a modest meal).
I had considered buying Bitcoin a decade ago and if I had, I'd be unbelievably wealthy today at current prices, with a billion dollars in value that I could cash out in about 5 minutes.
I've heard, and made, all the arguments against it and at the end of the day I was woefully detrimentally wrong. Cryptos offer the ability to do things no other "currency" can do with a main advantage of transportability instantly. It also offers near instant liquidity, and the potential for wealth creation like almost nothing else. It's a tool. Not the best tool or the worst tool but a tool.