How would you feel If I bought a house in 2017 for 200k usd. I hand you 10 bitcoin and today you decide to house hunt but just discovered your bitcoin is worth only 33k. That would mean bitcoin is about as good as Venezuelan currency against the USD. The price swings makes it useless as a means of exchange.
While I'll agree, you'll find that most of the current projects that legitimately hope to use blockchain as a payment system would not force you to transact in that manner.
Let's say you have Blockchain X (I'll just call it X) and you want to use it to buy a house. You link the X App to your bank account, select a payment address (given to you by the person selling the house), and then initiate a bank transfer. The slowest part of this transfer might be your bank sending along the money - right now, even "legit" crypto companies like exchanges take up to 4 days to pull money out of a bank account, unless you wire it for a fee. But let's assume someone has actually worked out a deal with the bank to initiate a transfer out of your account and to someone using the blockchain in a reasonable time frame. Perhaps you've signed up with your bank to facilitate effortless exchange between USD and a stablecoin (TUSD, DAI, USDC, etc)
So the money leaves your bank account, gets converted to an exchange token (let's use TUSD in this case) via oracles, and is sent to the target. The target gets TUSD, which is then converted BACK to USD (again via oracles), and then another
bank transfer is initiated to drop it into their account at the bank.
Alternatively, the oracle might convert to TUSD and then leave it that way, assuming the recipient wanted a blockchain asset rather than fiat.
At no point would anyone deliberately buy crypto at an exchange just to buy house, at least not unless they're insane or trying foolishly to drive adoption by avoiding sane payment tools.
Remember anyone can create a new coin, bitcon is just one of many coins. Bitcoin is based on nothing.
In this case, adoption matters. Bitcoin didn't gain value until people started mining it and getting involved in the project. Same goes for the other big chains. I can create my own blockchain and my own blockchain assets, but without a userbase, they'll have no value. Nobody will be trading in them. I can try some wash trading to create false value, yet no index will list those assets. In order for my crypto to have value, I have to create the entire ecosystem to go along with it, and I have to convince people to use some part of that ecosystem.
Now if someone creates a cryptocurrency and its backed by an audited gold store in a insured vault and its backed by a legitimate entity then I can see that cryptocurrency working. But bitcoin is based on nothing, zero. Its worse than fiat because there are no regulations or entity to back it and provide an orderly market etc..
There are cryptos that are based on USD bank reserves, like TUSD. They are (allegedly) audited, unlike USDT. I would be wary of a crypto based on a gold store unless the gold were stored someplace like Switzerland. In the US, physical gold HAS been confiscated in the past.
Cash, the same way they've always done it.
I'm more interested in seeing if the Darkweb marketplaces will continue to use Bitcoin if the value continues to drop, or if they will switch over to a more stable cryptocurrency that's tied to the price of something like a Euro or a Dollar. There are projects out there that are promising that.
The Darkweb uses XMR, not BTC. They'll continue to use XMR so long as it remains secure. It is devalued, but you'd better believe that the Darkwebbers know the risk and probably have multiple onramps and offramps so they can use the crashing market to increase their stack and come back out onto the illicit markets with larger amounts of cash to deal with changing prices.
The worst part is that Cryptos are a colossal waste of Energy and should be banned for that reason alone.
Outside of Bitcoin and maybe Ethereum, who else is using colossal amounts of energy in the cryptosphere?