I think the backdrop that's allowing cryptocurrency to flourish is rising state failure, globally, even in nations that we previously considered relatively stable & developed. People have a gut sense that the state can't protect them from the challenges that the next decade will bring, whether climate change, mass migrations, terrorism & extremism, inflation, a demographic bulge of young adults. They're looking for solutions that they personally can do in case the state either dissolves or becomes a hostile entity.
I think it's very likely that governments will outlaw cryptocurrency. But I also think it's likely that an increasingly larger portion of the global population is going to exist outside the law and outside the state. The government will say "Cryptocurrency is against the law", and a large fraction of people will say (quietly, unless they're stupid) "We don't care, because the alternatives you provide us are not working." Cryptocurrency is invaluable in that context, in providing a financial layer that does not require the state's power to enforce contracts.
And what exactly are you going to do with your illegal currency then? Apart from paying your drug dealer, I don't really see the use case.
It's already hard enough to launder cash, and that is the official currency! In addition money laundering regulations get tougher every day, so I'm afraid as an individual you'll just be able to send money to your friends, and potentially use it in holidays abroad (careful not to take any picture or let anybody know, more than one money laundering got caught by displaying vacations way above their declared income).
You use it to buy food, fix your house, pay off your protection racket that keeps the mob and/or police from killing you, get some car parts, pay that guy who loves cars to figure out why your transmission is busted, get antibiotics from the family that thought to loot the pharmacy, and of course convert into cash to pay the electric/Internet/phone companies so you can keep using Bitcoin, assuming they continue to exist (not a guarantee, and IMHO the weakest point in the "Bitcoin as a hedge against state failure" thesis). Plenty of people in failed states do this already.
I think most people in the developed world take for granted how much we get from a stable currency, rule of law, and public institutions that at least make an attempt to serve the public. All 3 of these are under threat right now.
Your assumption is that you can go to the grocery store, put your credit card into the self-checkout machine, and buy anything with money you earned several months ago. What happens when that money is worth less than half what it was last month? And grocers are like "Sorry, I don't take dollars, because they'll be worthless by the time I get my next delivery."
People in conditions like these survive by black markets. They pick something that can't be forged by a central bank - cigarettes, liquor, gold, seashells, whatever - and trade for goods with that. Cryptocurrency has the advantage of being worldwide (you can still get chips from Taiwan and electronic components from China), but the disadvantage of requiring electricity and the Internet to operate. Whether this is a winning combination depends on how deep the crisis is.
I think it's very likely that governments will outlaw cryptocurrency. But I also think it's likely that an increasingly larger portion of the global population is going to exist outside the law and outside the state. The government will say "Cryptocurrency is against the law", and a large fraction of people will say (quietly, unless they're stupid) "We don't care, because the alternatives you provide us are not working." Cryptocurrency is invaluable in that context, in providing a financial layer that does not require the state's power to enforce contracts.