Market capitalization is a metric that was invented for use in stock markets in order to give a price tag to companies, so that investors would know approximately how much money they would need to offer in order to buy out those companies.
This has ZERO MEANING in crypto, where it's impossible and pointless to buy every last microdecimal point of a currency. There is NO CURRENCY that is meaningfully measured by its market cap. No one says, "Oh, the market cap of the Japanese yen is $X trillion," because that's not how currencies are measured.
GDP is measured, yes. But GDP is a measurement of an economy's economic activity, not a way to measure currencies. If crypto analysts were honest, they'd try to measure crypto value using GDP, but crypto analysts also know that the actual GDP of crypto — including Bitcoin — is probably hilariously low compared to its "market cap" because trading activity generally isn't included in GDP. Which is probably why you don't see references to "the GDP of Bitcoin" or whatnot very often, if ever.
And people in crypto intuitively know this. You KNOW that if anyone tries to sell even 0.1% of Bitcoin, the "market cap" of Bitcoin will be plummet. Anyone who quotes "market cap" to you as a reason to feel confident in crypto is either uninformed or actively trying to deceive you.
"Market cap" for crypto is just another way to reiterate the price, but using bigger numbers, which is especially useful for small coins. It means absolutely nothing, and it is stupid that the crypto community harps it so much.
