I can definitely see a lot of cryptocurrencies losing a ton of a value but they do have a legitimate use for remittances. If you're transferring $1000 it doesn't matter if you convert it into 1 bitcoin or 100 bitcoins since your wife is cashing it out the next day for 20,000 pesos.
The fact is that billions in locked value have accrued securely over the years in battle tested protocols like curve, aave and yearn.
Doesn't matter if you own your keys if nobody wants to buy your Crypto/NFT etc.
Re your numbers, I'm afraid I don't trust any of the numbers in this market as none of them are audited.
You don’t have to. That’s the point. It’s a trustless infrastructure, with public data that anybody can audit. There are countless independent services that are reporting the same numbers, from querying the blockchain data.
So while the blockchains provide public records of transactions, the prices are not set by the blockchains and participants are anonymous enough to be difficult to track.
Many coins have failed, many more will fail, and many if not all will drop to zero as the mania subsides. When that happens it doesn’t matter where your keys are if the market turns illiquid in seconds during a crash.