Market cap is just number of stock x unit price. Apart from giving a (very rough) idea of how much it would cost to buy the company, it doesn’t say anything by itself. You can choose to see it as how a company is valuable if you think the market is efficient for that. But that high number could also be an accident of a handful speculative traders, because a variation in price change the whole market cap. Like if I pre mine a 1B of a crypto token and sell someone 1 for 1$ my token will have a market cap of 1B$, but that money is nowhere. The stock market could be more efficient, but there is no guarantee it is at time t for every stock.