(It seems clear to me that this isn't a valuable enough capability to justify the current price of BTC, but I guess that's a separate discussion.)
Yes, cycles of hype and supply and demand do distort stock prices, but it’s still a capital allocation market. GameStop can choose to sell shares into the hot market, much as AMC did, to raise money. Buyers of those shares are allocating capital into the company.
One of the draws of Bitcoin as a speculative instrument is that there are no fundamentals. Without fundamentals, there is no mechanism to suggest if it’s undervalued or overvalued. The only thing a Bitcoin purchase funds is more energy expenditure on mining.
What? Why not?
Not only can we continue to trade stock in a defunct corporation, we do. Take a look over here: https://www.liveauctioneers.com/item/85889867_imperial-india...
Trading happens on the pure derivative of stock prices, yeah, and people get rich off of it, sure, but ignoring the trillion dollars a year that flows from the profits on the economic activities of the S&P 500 back to the investors in the stock is ... oversimplifying things.
Even so, that figure isn't really relevant to the GP's point. Their point was that in addition to the price of the stocks, people who owned those stocks got cash money paid into their pockets, via dividends. That amounts to about 1.1% interest on money you spend buying the shares[1].
(That's not actually a great number. 2% is more common over the last 20 years. It suggests that as of right now the market is overpriced. But that's also for 2020, which is not a typical year. So far for 2021, it's more like 1.5%)
(My vague understanding is that for complicated and silly reasons, many more companies have preferred stock buybacks to dividends in recent decades, but it's still money flowing back from companies to investors.)
for traders, it's something that has a ticker, a price and some volume. whatever works.