Money needs to be able to buy stuff. That's always been a problem with cryptocurrency. The number of merchants who accept bitcoin directly is small, and converting bitcoin to cash dollars is nontrivial.
Background: The biggest cryptocurrency-to-dollars exchange in the early years of bitcoin was Mt. Gox, which imploded spectacularly in February 2014. Since then, the conversion problem has remained a very hard nut to crack, which is one reason why bitcoin derivatives were invented: You can now buy exposure to bitcoin without having to buy the currency itself.