Anything can be a means of exchange if enough people believe in it and agree to participate in it, whether it's backed by anything or absolutely nothing.
For me one of the main reasons not to use or trust bitcoin is that, supposedly, no one knows who actually started it or where the alleged creator of bitcoin currently is. It was supposedly started by some Asian guy (I can't recall his name at the top of my head) who has since seemingly disappeared off the face of the earth. I don't trust that. That whole story makes bitcoin suspicious from the get-go for me. Who tought it was necessary to launch this into the world? The Japanese Mafia? China? Who? I know who started the internet and to what end (DARPA/the American military, cos they needed a decentralized means of communication in the event of a nuclear war), I still don't know who's behind bitcoin or why they did it.
The main reason that most regular people opt out of trying out cryptocurrency is the complexity (it's really a currency for nerds, there's no way the average normie is every going to get into "bitcoin mining"), the false promises of privacy when it's very obviously not private as BurnerAccount pointed out, the fact that it's still taxed by your government, etc. Most of the stuff I want to buy I can buy with either cash or a card, so why would I go through the hassle of using crypto, unless it's to flash my nerd/darknet credentials? (And why would you do that if you really want to be incognito with your transactions?)
The only situation where crypto-money might be handy is in an extreme situation like the War in Ukraine or if your relative got kidnapped and you need to pay a ransom to the kidnappers or something. A number of Russian Youtubers who didn't want to be conscripted bought their way out of Russia and managed to stay out of the country after fleeing thanks to bitcoin donations, which was their only means of payment their Russian bank cards were rejected abroad due to the sanctions. I can imagine people being very glad they got into bitcoin in such a situation.
But still, no matter how noble you think this is, or how justifiable you think this use of bitcoin is for someone escaping sure death in a war... you're still using bitcoin to break the law essentially, thus contributing to its already questionable status as a black market currency used for unlawful transactions. Should someone's ability to escape sure death in a war be contingent on whether they're terminally online enough to get into bitcoin?