I can think of at least two real-world uses where cryptocurrency is a better choice than fiat: (1) sending money overseas with very low transaction fee, and (2) transacting on the black market.
> sending money overseas with very low transaction fee
Except that fluctuations in the conversion rate make this very touchy, especially if you're talking about a significant sum of money. Also, sending crypto anywhere outside of a handful of developed nations is fraught with difficulty because recipients need to be able to convert bitcoin into spendable money which often involves risky in-person meetups and gigantic markups on the conversion rate.
These are market problems that are especially suited for developing nations to be able to solve themselves. I am forever impressed by the ability of local populations to work out collective solutions to scaling and trust problems.
Also, having options is better than not having them. Sure, there's the international wire system, but it wouldn't hurt to give it some competition.
I'm not saying cryptocurrencies shouldn't exist, only that they are not at this time a serious or practical alternative except for very unique scenarios that are generally outside the scope of the average citizen, especially in the developing world. In the developing world, very often, even access to computers, electricity, and internet are serious obstacles, not to mention a gap in technical literacy compared to the developed world.
>difficulty because recipients need to be able to convert ? bitcoin into spendable money which often involves risky in-person meetups and gigantic markups on the conversion rate.
Except that fluctuations in the conversion rate make this very touchy, especially if you're talking about a significant sum of money. Also, sending crypto anywhere outside of a handful of developed nations is fraught with difficulty because recipients need to be able to convert bitcoin into spendable money which often involves risky in-person meetups and gigantic markups on the conversion rate.