But Bitcoin is just a pyramid scheme. It has no true value or tangible benefit.
I suspect you mean to say that it is merely speculative, as a pyramid scheme is something very specific that does not describe cryptocurrency. The value that cryptocurrency has is exactly the value that people agree that it has, just like any other fiat currency. The $20 bill in your wallet is not intrinsically worth two meal combos at McDonald's, it's just a marker for barter value that society has a general agreement of how much it is worth. If everybody agreed that dead ladybugs were currency, we could use them as such. There is, despite your reluctance, a widespread agreement among a lot of people (not all people) that cryptocurrency is currency. Heck, to get on topic, the Sacramento Kings at one point in time would accept payment for tickets in Bitcoin (I don't know if they still do).
Is there a risk that people stop agreeing on the value of cryptocurrency and it crashes? Sure. But the longer it is around, and the more accepted it becomes as a "true" currency, the less likely that seems to be.
Cash is backed, regulated, and supported by the government expressly to facilitate the extended barter system world governments depend upon.
I would argue that with the demise of the gold standard, the U.S. government does not in fact back its money. Try taking your $20 bill to a Federal Reserve bank and asking them to exchange it for gold, see what happens. $USD have value because people believe that $USD are relatively stable - because there is a widespread agreement on how much they are worth that doesn't change rapidly due to the large number of people that use them, and because there is faith that the U.S. government won't just go around printing these:
People have mentioned the FDIC above, but that doesn't back $USD. The FDIC is insurance against bank collapse, which is a completely different thing. Banks do things with money that are are risky. They don't hold cash reserves equal to their deposits, rather they lend the money out and count on statistics to ensure that they can cover withdrawal demand. If they can't cover withdrawal demand, bad stuff happens, and that's what the FDIC protects against. To my understanding, there is no analogous notion of a "bank" with cryptocurrency. When you own the Bitcoin, you own the Bitcoin, and even if it is "held" at an "exchange", it's immediately available. There can't be a "run on Bitcoin". So in that sense, the FDIC doesn't represent a sort of government backing that is lacking in cryptocurrency, but rather it represents insurance against a catastrophic event that is not relevant for cryptocurrency.
But Bitcoin is like an NFT - there is no real value to a purely digital contrivance that isn't backed by anything. It only has value because you think it does and you can convince someone else to spend their $$$ to buy it at a higher price than you paid, not because of any actual value or financial backing.
Just like $USD. You seem to be attaching an inherent value to centralized currency that you deny to decentralized currency. I don't agree that that's the case.
And it keeps trying to sucker in more people to spend more and more money on a product that doesn't actually exist. It's a hackable computer file. That's it.
Again, hackable computer files are currency if people treat them as currency. And let's not forget that $USD are also susceptible to theft and fraud. Credit card fraud alone comes up to $30B a year. Paper money can be counterfeited. Currency has been subject to fraud since the dawn of currency, and always will be.
Bitcoin could all come crashing down tomorrow and the world wouldn't skip a beat, except for a few ultra-millionaires that would lose some of their extra yacht or cocaine habit money. If the US economy (backer of US $$$) did that instead, there would be real ramifications as the world's largest economy would grind to a halt.
This is true. But the reason for this is the vast size of the difference between the prevalence of $USD relative to Bitcoin. If Bitcoin were used for >99% of all transactions in the U.S. and $USD were used for <1%, I can guarantee you that the relative significance of Bitcoin/$USD crashes would be reversed.
I do not dispute that Bitcoin is not a widely prevalent currency, nor do I dispute the ramifications of of a current Bitcoin collapse. But that doesn't mean that cryptocurrency is not currency, and it does not mean that cryptocurrency will not gain in prevalence and importance in the future. As I have said elsewhere, I suspect cryptocurrency will increase its market share in the future, not decrease.
Cash/credit are easier to use and do not require constant use of immense amounts of natural resources
This is also true. But I suspect that this will change in the future. Credit cards used to be difficult to use. You had to put a carbon paper into a little machine and make a copy of the card info, which then had to be subsequently entered by hand into a ledger by a human. A great many places wouldn't even take credit cards. Now you find kids with lemonade stands that have credit card scanners on their iPads. Why would we think that cryptocurrency usage will remain tedious when everything that we know about technological progress says otherwise? The issue of the energy required to mine crypto is also real, but the majority of it is due to the "proof-of-work" paradigm, where large numbers of miners are simultaneously competing to do the work required for each transaction, there is only one "winner", and the energy expended by the losers is wasted. Undoubtedly cryptocurrency will eventually move to a "proof-of-stake" paradigm, where one miner is chosen to do the work for each transaction, which will cut energy expenditure enormously.
And again, I don't even hold any cryptocurrency. I'm not doing this out of some sort of defense of my own assets. I just think - as someone who (I believe like you) reads/watches a good amount of sci-fi and thinks about the future and technological advances - that a substantial move towards decentralized cryptocurrencies is probably inevitable, and the only question is how long it will take to be realized and which cryptocurrencies survive. Will a big shift happen in ten years? Probably not. Two hundred years? Heck yeah. And so the idea that cryptocurrency is "not currency" strikes me as a very outdated, hey-you-kids-get-off-my-lawn way of thinking.